Document:

EX-10.1

 Exhibit 10.1 

CODIAK BIOSCIENCES, INC. 

2015 STOCK OPTION AND GRANT PLAN 
  

	SECTION 1.	 GENERAL PURPOSE OF THE PLAN; DEFINITIONS 

The name of the plan is the Codiak BioSciences, Inc. 2015 Stock Option and Grant Plan (the “Plan”). The purpose of the Plan is to
encourage and enable the officers, employees, directors, Consultants and other key persons of Codiak BioSciences, Inc., a Delaware corporation (including any successor entity, the “Company”), and its Subsidiaries, upon whose judgment,
initiative and efforts the Company largely depends for the successful conduct of its business, to acquire a proprietary interest in the Company. 

The following terms shall be defined as set forth below: 

“Affiliate” of any Person means a Person that directly or indirectly, through one or more intermediaries, controls, is
controlled by or is under common control with the first mentioned Person. A Person shall be deemed to control another Person if such first Person possesses directly or indirectly the power to direct, or cause the direction of, the management and
policies of the second Person, whether through the ownership of voting securities, by contract or otherwise. 
 “Award” or
“Awards,” except where referring to a particular category of grant under the Plan, shall include Incentive Stock Options, Non-Qualified Stock Options, Restricted Stock Awards, Unrestricted
Stock Awards, Restricted Stock Units or any combination of the foregoing. 
 “Award Agreement” means a
written or electronic agreement setting forth the terms and provisions applicable to an Award granted under the Plan. Each Award Agreement may contain terms and conditions in addition to those set forth in the Plan; provided, however,
in the event of any conflict in the terms of the Plan and the Award Agreement, the terms of the Plan shall govern. 

“Board” means the Board of Directors of the Company. 

“Cause” shall have the meaning as set forth in the Award Agreement(s). In the case that any Award Agreement does not contain
a definition of “Cause,” it shall mean (i) the grantee’s dishonest statements or acts with respect to the Company or any Affiliate of the Company, or any current or prospective customers, suppliers vendors or other third parties
with which such entity does business; (ii) the grantee’s commission of (A) a felony or (B) any misdemeanor involving moral turpitude, deceit, dishonesty or fraud; (iii) the grantee’s failure to perform his assigned
duties and responsibilities to the reasonable satisfaction of the Company which failure continues, in the reasonable judgment of the Company, after written notice given to the grantee by the Company; (iv) the grantee’s gross negligence,
willful misconduct or insubordination with respect to the Company or any Affiliate of the Company; or (v) the grantee’s material violation of any provision of any agreement(s) between the grantee and the Company relating to noncompetition,
nonsolicitation, nondisclosure and/or assignment of inventions. 

  
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 “Chief Executive Officer” means the Chief Executive Officer of the Company
or, if there is no Chief Executive Officer, then the President of the Company. 
 “Code” means the Internal Revenue Code of
1986, as amended, and any successor Code, and related rules, regulations and interpretations. 
 “Committee” means the
Committee of the Board referred to in Section 2. 
 “Consultant” means any natural person that provides bona fide
services to the Company (including a Subsidiary), and such services are not in connection with the offer or sale of securities in a capital-raising transaction and do not directly or indirectly promote or maintain a market for the Company’s
securities. 
 “Disability” means “disability” as defined in Section 422(c) of the Code. 

“Effective Date” means the date on which the Plan is adopted as set forth on the final page of the Plan. 

“Exchange Act” means the Securities Exchange Act of 1934, as amended, and the rules and regulations thereunder. 

“Fair Market Value” of the Stock on any given date means the fair market value of the Stock determined in good faith by the
Committee based on the reasonable application of a reasonable valuation method not inconsistent with Section 409A of the Code. If the Stock is admitted to trade on a national securities exchange, the determination shall be made by reference to
the closing price reported on such exchange. If there is no closing price for such date, the determination shall be made by reference to the last date preceding such date for which there is a closing price. If the date for which Fair Market Value is
determined is the first day when trading prices for the Stock are reported on a national securities exchange, the Fair Market Value shall be the “Price to the Public” (or equivalent) set forth on the cover page for the final prospectus
relating to the Company’s Initial Public Offering. 
 “Good Reason” shall have the meaning as set forth in the Award
Agreement(s). In the case that any Award Agreement does not contain a definition of “Good Reason,” it shall mean (i) a material diminution in the grantee’s base salary except for across-the-board salary reductions similarly affecting all or substantially all similarly situated employees of the Company or (ii) a change of more than 50 miles in the geographic location at which the
grantee provides services to the Company, so long as the grantee provides at least 90 days’ notice to the Company following the initial occurrence of any such event and the Company fails to cure such event within 30 days thereafter. 

“Grant Date” means the date that the Committee designates in its approval of an Award in accordance with applicable law as
the date on which the Award is granted, which date may not precede the date of such Committee approval. 
 “Holder” means,
with respect to an Award or any Shares, the Person holding such Award or Shares, including the initial recipient of the Award or any Permitted Transferee. 

  
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 “Incentive Stock Option” means any Stock Option designated and qualified as
an “incentive stock option” as defined in Section 422 of the Code. 
 “Initial Public Offering” means the
consummation of the first firm commitment underwritten public offering pursuant to an effective registration statement under the Securities Act covering the offer and sale by the Company of its equity securities, as a result of or following which
the Stock shall be publicly held. 
 “Non-Qualified Stock Option” means any Stock
Option that is not an Incentive Stock Option. 
 “Option” or “Stock Option” means any option to purchase
shares of Stock granted pursuant to Section 5. 
 “Permitted Transferees” shall mean any of the following to whom a
Holder may transfer Shares hereunder (as set forth in Section 9(a)(ii)(A)): the Holder’s child, stepchild, grandchild, parent, stepparent, grandparent, spouse, former spouse, sibling, niece, nephew, mother-in-law, father-in-law, son-in-law, daughter-in-law, brother-in-law, or sister-in-law, including adoptive relationships, any person sharing the Holder’s household (other than a tenant or employee), a trust in which these persons have more than fifty percent of the beneficial
interest, a foundation in which these persons control the management of assets, and any other entity in which these persons own more than fifty percent of the voting interests; provided, however, that any such trust does not require or permit
distribution of any Shares during the term of the Award Agreement unless subject to its terms. Upon the death of the Holder, the term Permitted Transferees shall also include such deceased Holder’s estate, executors, administrators, personal
representatives, heirs, legatees and distributees, as the case may be. 
 “Person” shall mean any individual, corporation,
partnership (limited or general), limited liability company, limited liability partnership, association, trust, joint venture, unincorporated organization or any similar entity. 

“Restricted Stock Award” means Awards granted pursuant to Section 6 and “Restricted Stock” means Shares
issued pursuant to such Awards. 
 “Restricted Stock Unit” means an Award of phantom stock units to a grantee, which may be
settled in cash or Shares as determined by the Committee, pursuant to Section 8. 
 “Sale Event” means the
consummation of (i) the dissolution or liquidation of the Company, (ii) the sale of all or substantially all of the assets of the Company on a consolidated basis to an unrelated person or entity, (iii) a merger, reorganization or
consolidation pursuant to which the holders of the Company’s outstanding voting power immediately prior to such transaction do not own a majority of the outstanding voting power of the surviving or resulting entity (or its ultimate parent, if
applicable), (iv) the acquisition of all or a majority of the outstanding voting stock of the Company in a single transaction or a series of related transactions by a Person or group of Persons, or (v) any other acquisition of the business of
the Company, as determined by the Board; provided, however, that the Company’s Initial Public Offering, any subsequent public offering or another capital raising event, or a merger effected solely to change the Company’s domicile
shall not constitute a “Sale Event.” 

  
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 “Section 409A” means Section 409A of the Code and
the regulations and other guidance promulgated thereunder. 
 “Securities Act” means the Securities Act of 1933, as
amended, and the rules and regulations thereunder. 
 “Service Relationship” means any relationship as a full-time
employee, part-time employee, director or other key person (including Consultants) of the Company or any Subsidiary or any successor entity (e.g., a Service Relationship shall be deemed to continue without interruption in the event an
individual’s status changes from full-time employee to part-time employee or Consultant). 
 “Shares” means shares of
Stock. 
 “Stock” means the Class A Common Stock, par value $0.0001 per share, of the Company. 

“Subsidiary” means any corporation or other entity (other than the Company) in which the Company has more than a
50 percent interest, either directly or indirectly. 
 “Ten Percent Owner” means an employee who owns or is deemed to
own (by reason of the attribution rules of Section 424(d) of the Code) more than 10 percent of the combined voting power of all classes of stock of the Company or any parent of the Company or any Subsidiary. 

“Termination Event” means the termination of the Award recipient’s Service Relationship with the Company and its
Subsidiaries for any reason whatsoever, regardless of the circumstances thereof, and including, without limitation, upon death, disability, retirement, discharge or resignation for any reason, whether voluntarily or involuntarily. The following
shall not constitute a Termination Event: (i) a transfer to the service of the Company from a Subsidiary or from the Company to a Subsidiary, or from one Subsidiary to another Subsidiary or (ii) an approved leave of absence for military
service or sickness, or for any other purpose approved by the Committee, if the individual’s right to re-employment is guaranteed either by a statute or by contract or under the policy pursuant to which
the leave of absence was granted or if the Committee otherwise so provides in writing. 
 “Unrestricted Stock Award” means
any Award granted pursuant to Section 7 and “Unrestricted Stock” means Shares issued pursuant to such Awards. 
  

	SECTION 2.	 ADMINISTRATION OF PLAN; COMMITTEE AUTHORITY TO SELECT GRANTEES AND DETERMINE AWARDS

 (a)    Administration of Plan. The Plan shall be administered by the Board, or at the
discretion of the Board, by a committee of the Board, comprised of not less than two directors. All references herein to the “Committee” shall be deemed to refer to the group then responsible for administration of the Plan at the relevant
time (i.e., either the Board of Directors or a committee or committees of the Board, as applicable). 
 (b)    Powers
of Committee. The Committee shall have the power and authority to grant Awards consistent with the terms of the Plan, including the power and authority: 

(i)    to select the individuals to whom Awards may from time to time be granted; 

  
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 (ii)    to determine the time or times of grant, and the amount, if any,
of Incentive Stock Options, Non-Qualified Stock Options, Restricted Stock Awards, Unrestricted Stock Awards, Restricted Stock Units, or any combination of the foregoing, granted to any one or more grantees;

 (iii)    to determine the number of Shares to be covered by any Award and, subject to the provisions of the Plan, the
price, exercise price, conversion ratio or other price relating thereto; 
 (iv)    to determine and, subject to
Section 12, to modify from time to time the terms and conditions, including restrictions, not inconsistent with the terms of the Plan, of any Award, which terms and conditions may differ among individual Awards and grantees, and to approve the
form of Award Agreements; 
 (v)    to accelerate at any time the exercisability or vesting of all or any portion of any
Award; 
 (vi)    to impose any limitations on Awards, including limitations on transfers, repurchase provisions and the
like, and to exercise repurchase rights or obligations; 
 (vii)    subject to Section 5(a)(ii) and any restrictions
imposed by Section 409A, to extend at any time the period in which Stock Options may be exercised; and 

(viii)    at any time to adopt, alter and repeal such rules, guidelines and practices for administration of the Plan and
for its own acts and proceedings as it shall deem advisable; to interpret the terms and provisions of the Plan and any Award (including Award Agreements); to make all determinations it deems advisable for the administration of the Plan; to decide
all disputes arising in connection with the Plan; and to otherwise supervise the administration of the Plan. 
 All decisions and interpretations of the
Committee shall be binding on all persons, including the Company and all Holders. 
 (c)    Award Agreement.
Awards under the Plan shall be evidenced by Award Agreements that set forth the terms, conditions and limitations for each Award. 

(d)    Indemnification. Neither the Board nor the Committee, nor any member of either or any delegate thereof, shall
be liable for any act, omission, interpretation, construction or determination made in good faith in connection with the Plan, and the members of the Board and the Committee (and any delegate thereof) shall be entitled in all cases to
indemnification and reimbursement by the Company in respect of any claim, loss, damage or expense (including, without limitation, reasonable attorneys’ fees) arising or resulting therefrom to the fullest extent permitted by law and/or under the
Company’s governing documents, including its certificate of incorporation or bylaws, or any directors’ and officers’ liability insurance coverage which may be in effect from time to time and/or any indemnification agreement between
such individual and the Company. 

  
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 (e)    Foreign Award Recipients. Notwithstanding any provision of
the Plan to the contrary, in order to comply with the laws in other countries in which the Company and any Subsidiary operate or have employees or other individuals eligible for Awards, the Committee, in its sole discretion, shall have the power and
authority to: (i) determine which Subsidiaries, if any, shall be covered by the Plan; (ii) determine which individuals, if any, outside the United States are eligible to participate in the Plan; (iii) modify the terms and conditions
of any Award granted to individuals outside the United States to comply with applicable foreign laws; (iv) establish subplans and modify exercise procedures and other terms and procedures, to the extent the Committee determines such actions to
be necessary or advisable (and such subplans and/or modifications shall be attached to the Plan as appendices); provided, however, that no such subplans and/or modifications shall increase the share limitation contained in
Section 3(a) hereof; and (v) take any action, before or after an Award is made, that the Committee determines to be necessary or advisable to obtain approval or comply with any local governmental regulatory exemptions or approvals.

  

	SECTION 3.	 STOCK ISSUABLE UNDER THE PLAN; MERGERS AND OTHER TRANSACTIONS; SUBSTITUTION 

(a)    Stock Issuable. The maximum number of Shares reserved and available for issuance under the Plan shall be
8,400,000 Shares, subject to adjustment as provided in Section 3(b). For purposes of this limitation, the Shares underlying any Awards that are forfeited, canceled, reacquired by the Company prior to vesting, satisfied without the
issuance of Stock or otherwise terminated (other than by exercise) and Shares that are withheld upon exercise of an Option or settlement of an Award to cover the exercise price or tax withholding shall be added back to the Shares available for
issuance under the Plan. Subject to such overall limitations, Shares may be issued up to such maximum number pursuant to any type or types of Award, and no more than 8,400,000 Shares may be issued pursuant to Incentive Stock Options. The Shares
available for issuance under the Plan may be authorized but unissued Shares or Shares reacquired by the Company. Beginning on the date that the Company becomes subject to Section 162(m) of the Code, Options with respect to no more than
8,400,000 Shares shall be granted to any one individual in any calendar year period. 
 (b)    Changes in Stock.
Subject to Section 3(c) hereof, if, as a result of any reorganization, recapitalization, reclassification, stock dividend, stock split, reverse stock split or other similar change in the Company’s capital stock, the outstanding Shares are
increased or decreased or are exchanged for a different number or kind of shares or other securities of the Company, or additional Shares or new or different shares or other securities of the Company or other
non-cash assets are distributed with respect to such Shares or other securities, in each case, without the receipt of consideration by the Company, or, if, as a result of any merger or consolidation, or sale
of all or substantially all of the assets of the Company, the outstanding Shares are converted into or exchanged for other securities of the Company or any successor entity (or a parent or subsidiary thereof), the Committee shall make an appropriate
and proportionate adjustment in (i) the maximum number of Shares reserved for issuance under the Plan, (ii) the number and kind of Shares or other securities subject to any then outstanding Awards under the Plan, (iii) the repurchase
price, if any, per Share subject to each outstanding Award, and (iv) the exercise price for each Share subject to any then outstanding Stock Options under the Plan, without changing the aggregate exercise price (i.e., the exercise price
multiplied by the number of Stock 

  
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Options) as to which such Stock Options remain exercisable. The adjustment by the Committee shall be final, binding and conclusive. No fractional Shares shall be issued under the Plan resulting
from any such adjustment, but the Committee in its discretion may make a cash payment in lieu of fractional shares. 

(c)    Sale Events. 

(i)    Options. 

(A)    In the case of and subject to the consummation of a Sale Event, the Plan and all outstanding Options
issued hereunder shall terminate upon the effective time of any such Sale Event unless assumed or continued by the successor entity, or new stock options or other awards of the successor entity or parent thereof are substituted therefor, with an equitable or proportionate adjustment as to the number and kind of shares and, if appropriate, the per share exercise prices, as such parties shall agree (after taking into account any
acceleration hereunder and/or pursuant to the terms of any Award Agreement). 
 (B)    In the event of
the termination of the Plan and all outstanding Options issued hereunder pursuant to Section 3(c), each Holder of Options shall be permitted, within a period of time prior to the consummation of the Sale Event as specified by the Committee, to
exercise all such Options which are then exercisable or will become exercisable as of the effective time of the Sale Event; provided, however, that the exercise of Options not exercisable prior to the Sale Event shall be subject to the
consummation of the Sale Event. 
 (C)    Notwithstanding anything to the contrary in
Section 3(c)(i)(A), in the event of a Sale Event, the Company shall have the right, but not the obligation, to make or provide for a cash payment to the Holders of Options, without any consent of the Holders, in exchange for the cancellation
thereof, in an amount equal to the difference between (A) the value as determined by the Committee of the consideration payable per share of Stock pursuant to the Sale Event (the “Sale Price”) times the number of Shares subject to
outstanding Options being cancelled (to the extent then vested and exercisable, including by reason of acceleration in connection with such Sale Event, at prices not in excess of the Sale Price) and (B) the aggregate exercise price of all such
outstanding vested and exercisable Options. 
 (ii)    Restricted Stock and Restricted Stock Unit Awards. 

(A)    In the case of and subject to the consummation of a Sale Event, all unvested Restricted Stock and
unvested Restricted Stock Unit Awards (other than those becoming vested as a result of the Sale Event) issued hereunder shall be forfeited immediately prior to the effective time of any such Sale Event unless assumed or continued by the successor
entity, or awards of the successor entity or parent thereof are substituted therefor, with an equitable or proportionate adjustment as to the number and kind of shares subject to such awards as such parties shall agree (after taking into account any
acceleration hereunder and/or pursuant to the terms of any Award Agreement). 

  
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 (B)    In the event of the forfeiture of Restricted
Stock pursuant to Section 3(c)(ii)(A), such Restricted Stock shall be repurchased from the Holder thereof at a price per share equal to the original per share purchase price paid by the Holder (subject to adjustment as provided in
Section 3(b)) for such Shares. 
 (C)    Notwithstanding anything to the contrary in
Section 3(c)(ii)(A), in the event of a Sale Event, the Company shall have the right, but not the obligation, to make or provide for a cash payment to the Holders of Restricted Stock or Restricted Stock Unit Awards, without consent of the
Holders, in exchange for the cancellation thereof, in an amount equal to the Sale Price times the number of Shares subject to such Awards, to be paid at the time of such Sale Event or upon the later vesting of such Awards. 

 

	SECTION 4.	 ELIGIBILITY 

Grantees under the Plan will be such full or part-time officers and other employees, directors, Consultants and key persons of the Company and
any Subsidiary who are selected from time to time by the Committee in its sole discretion; provided, however, that Awards shall be granted only to those individuals described in Rule 701(c) of the Securities Act. 

 

	SECTION 5.	 STOCK OPTIONS 

Upon the grant of a Stock Option, the Company and the grantee shall enter into an Award Agreement. The terms and conditions of each such Award
Agreement shall be determined by the Committee, and such terms and conditions may differ among individual Awards and grantees. 
 Stock
Options granted under the Plan may be either Incentive Stock Options or Non-Qualified Stock Options. Incentive Stock Options may be granted only to employees of the Company or any Subsidiary that is a
“subsidiary corporation” within the meaning of Section 424(f) of the Code. To the extent that any Option does not qualify as an Incentive Stock Option, it shall be deemed a Non-Qualified Stock
Option. 
 (a)    Terms of Stock Options. The Committee in its discretion may grant Stock Options to those
individuals who meet the eligibility requirements of Section 4. Stock Options shall be subject to the following terms and conditions and shall contain such additional terms and conditions, not inconsistent with the terms of the Plan, as the
Committee shall deem desirable. 
 (i)    Exercise Price. The exercise price per share for the Shares covered by a
Stock Option shall be determined by the Committee at the time of grant but shall not be less than 100 percent of the Fair Market Value on the Grant Date. In the case of an Incentive Stock Option that is granted to a Ten Percent Owner, the
exercise price per share for the Shares covered by such Incentive Stock Option shall not be less than 110 percent of the Fair Market Value on the Grant Date. 

(ii)    Option Term. The term of each Stock Option shall be fixed by the Committee, but no Stock Option shall be
exercisable more than ten years from the Grant Date. In the case of an Incentive Stock Option that is granted to a Ten Percent Owner, the term of such Stock Option shall be no more than five years from the Grant Date. 

  
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 (iii)    Exercisability; Rights of a Stockholder. Stock Options
shall become exercisable and/or vested at such time or times, whether or not in installments, as shall be determined by the Committee at or after the Grant Date. The Award Agreement may permit a grantee to exercise all or a portion of a Stock Option
immediately at grant; provided that the Shares issued upon such exercise shall be subject to restrictions and a vesting schedule identical to the vesting schedule of the related Stock Option, such Shares shall be deemed to be Restricted Stock for
purposes of the Plan, and the optionee may be required to enter into an additional or new Award Agreement as a condition to exercise of such Stock Option. An optionee shall have the rights of a stockholder only as to Shares acquired upon the
exercise of a Stock Option and not as to unexercised Stock Options. An optionee shall not be deemed to have acquired any Shares unless and until a Stock Option shall have been exercised pursuant to the terms of the Award Agreement and this Plan and
the optionee’s name has been entered on the books of the Company as a stockholder. 
 (iv)    Method of
Exercise. Stock Options may be exercised by an optionee in whole or in part, by the optionee giving written or electronic notice of exercise to the Company, specifying the number of Shares to be purchased. Payment of the purchase price may be
made by one or more of the following methods (or any combination thereof) to the extent provided in the Award Agreement: 

(A)    In cash, by certified or bank check, by wire transfer of immediately available funds, or other
instrument acceptable to the Committee; 
 (B)    If permitted by the Committee, by the optionee
delivering to the Company a promissory note, if the Board has expressly authorized the loan of funds to the optionee for the purpose of enabling or assisting the optionee to effect the exercise of his or her Stock Option; provided, that at
least so much of the exercise price as represents the par value of the Stock shall be paid in cash if required by state law; 

(C)    If permitted by the Committee and the Initial Public Offering has occurred (or the Stock otherwise
becomes publicly-traded), through the delivery (or attestation to the ownership) of Shares that have been purchased by the optionee on the open market or that are beneficially owned by the optionee and are not then subject to restrictions under any
Company plan. To the extent required to avoid variable accounting treatment under ASC 718 or other applicable accounting rules, such surrendered Shares if originally purchased from the Company shall have been owned by the optionee for at least six
months. Such surrendered Shares shall be valued at Fair Market Value on the exercise date; 
 (D)    If
permitted by the Committee and the Initial Public Offering has occurred (or the Stock otherwise becomes publicly-traded), by the optionee delivering to the Company a properly executed exercise notice together with irrevocable instructions to a
broker to promptly deliver to the Company cash or a check payable and acceptable to the Company for the purchase price; provided that in the event the optionee chooses to pay the purchase price as so provided, the optionee and the broker
shall comply with such procedures and enter into such agreements of indemnity and other agreements as the Committee shall prescribe as a condition of such payment procedure; or 

  
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 (E)    If permitted by the Committee, and only with
respect to Stock Options that are not Incentive Stock Options, by a “net exercise” arrangement pursuant to which the Company will reduce the number of Shares issuable upon exercise by the largest whole number of Shares with a Fair Market
Value that does not exceed the aggregate exercise price. 
 Payment instruments will be received subject to collection. No certificates for
Shares so purchased will be issued to the optionee or, with respect to uncertificated Stock, no transfer to the optionee on the records of the Company will take place, until the Company has completed all steps it has deemed necessary to satisfy
legal requirements relating to the issuance and sale of the Shares, which steps may include, without limitation, (i) receipt of a representation from the optionee at the time of exercise of the Option that the optionee is purchasing the Shares
for the optionee’s own account and not with a view to any sale or distribution of the Shares or other representations relating to compliance with applicable law governing the issuance of securities, (ii) the legending of the certificate
(or notation on any book entry) representing the Shares to evidence the foregoing restrictions, and (iii) obtaining from optionee payment or provision for all withholding taxes due as a result of the exercise of the Option. The delivery of
certificates representing the shares of Stock (or the transfer to the optionee on the records of the Company with respect to uncertificated Stock) to be purchased pursuant to the exercise of a Stock Option will be contingent upon (A) receipt
from the optionee (or a purchaser acting in his or her stead in accordance with the provisions of the Stock Option) by the Company of the full purchase price for such Shares and the fulfillment of any other requirements contained in the Award
Agreement or applicable provisions of laws and (B) if required by the Company, the optionee shall have entered into any stockholders agreements or other agreements with the Company and/or certain other of the Company’s stockholders
relating to the Stock. In the event an optionee chooses to pay the purchase price by previously-owned Shares through the attestation method, the number of Shares transferred to the optionee upon the exercise of the Stock Option shall be net of the
number of Shares attested to. 
 (b)    Annual Limit on Incentive Stock Options. To the extent required for
“incentive stock option” treatment under Section 422 of the Code, the aggregate Fair Market Value (determined as of the Grant Date) of the Shares with respect to which Incentive Stock Options granted under the Plan and any other plan
of the Company or its parent and any Subsidiary that become exercisable for the first time by an optionee during any calendar year shall not exceed $100,000 or such other limit as may be in effect from time to time under Section 422 of the
Code. To the extent that any Stock Option exceeds this limit, it shall constitute a Non-Qualified Stock Option. 

(c)    Termination. Any portion of a Stock Option that is not vested and exercisable on the date of termination of
an optionee’s Service Relationship shall immediately expire and be null and void. Once any portion of the Stock Option becomes vested and exercisable, the optionee’s right to exercise such portion of the Stock Option (or the
optionee’s representatives and legatees as applicable) in the event of a termination of the optionee’s Service Relationship shall continue until the earliest of: (i) the date which is: (A) 12 months following the date on which the
optionee’s Service Relationship terminates due to death or Disability (or such longer period of time as determined by the Committee and set forth in the applicable Award Agreement), or (B) three months following the date on which the
optionee’s Service Relationship terminates if the termination is due to any reason other than death or Disability (or such longer period of time as 

  
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determined by the Committee and set forth in the applicable Award Agreement), or (ii) the Expiration Date set forth in the Award Agreement; provided that notwithstanding the
foregoing, an Award Agreement may provide that if the optionee’s Service Relationship is terminated for Cause, the Stock Option shall terminate immediately and be null and void upon the date of the optionee’s termination and shall not
thereafter be exercisable. 
  

	SECTION 6.	 RESTRICTED STOCK AWARDS 

(a)    Nature of Restricted Stock Awards. The Committee may, in its sole discretion, grant (or sell at par value or
such other purchase price determined by the Committee) to an eligible individual under Section 4 hereof a Restricted Stock Award under the Plan. The Committee shall determine the restrictions and conditions applicable to each Restricted Stock
Award at the time of grant. Conditions may be based on continuing employment (or other Service Relationship), achievement of pre-established performance goals and objectives and/or such other criteria as the
Committee may determine. Upon the grant of a Restricted Stock Award, the Company and the grantee shall enter into an Award Agreement. The terms and conditions of each such Award Agreement shall be determined by the Committee, and such terms and
conditions may differ among individual Awards and grantees. 
 (b)    Rights as a Stockholder. Upon the grant of
the Restricted Stock Award and payment of any applicable purchase price, a grantee of Restricted Stock shall be considered the record owner of and shall be entitled to vote the Restricted Stock if, and to the extent, such Shares are entitled to
voting rights, subject to such conditions contained in the Award Agreement. The grantee shall be entitled to receive all dividends and any other distributions declared on the Shares; provided, however, that the Company is under no duty
to declare any such dividends or to make any such distribution. Unless the Committee shall otherwise determine, certificates evidencing the Restricted Stock shall remain in the possession of the Company until such Restricted Stock is vested as
provided in subsection (d) below of this Section, and the grantee shall be required, as a condition of the grant, to deliver to the Company a stock power endorsed in blank and such other instruments of transfer as the Committee may prescribe.

 (c)    Restrictions. Restricted Stock may not be sold, assigned, transferred, pledged or otherwise encumbered
or disposed of except as specifically provided herein or in the Award Agreement. Except as may otherwise be provided by the Committee either in the Award Agreement or, subject to Section 12 below, in writing after the Award Agreement is issued,
if a grantee’s Service Relationship with the Company and any Subsidiary terminates, the Company or its assigns shall have the right, as may be specified in the relevant instrument, to repurchase some or all of the Shares subject to the Award at
such purchase price as is set forth in the Award Agreement. 
 (d)    Vesting of Restricted Stock. The Committee
at the time of grant shall specify in the Award Agreement the date or dates and/or the attainment of pre-established performance goals, objectives and other conditions on which the substantial risk of
forfeiture imposed shall lapse and the Restricted Stock shall become vested, subject to such further rights of the Company or its assigns as may be specified in the Award Agreement. 

  
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	SECTION 7.	 UNRESTRICTED STOCK AWARDS 

The Committee may, in its sole discretion, grant (or sell at par value or such other purchase price determined by the Committee) to an eligible
person under Section 4 hereof an Unrestricted Stock Award under the Plan. Unrestricted Stock Awards may be granted in respect of past services or other valid consideration, or in lieu of cash compensation due to such grantee. 

 

	SECTION 8.	 RESTRICTED STOCK UNITS 

(a)    Nature of Restricted Stock Units. The Committee may, in its sole discretion, grant to an eligible person
under Section 4 hereof Restricted Stock Units under the Plan. The Committee shall determine the restrictions and conditions applicable to each Restricted Stock Unit at the time of grant. Vesting conditions may be based on continuing employment
(or other Service Relationship), achievement of pre-established performance goals and objectives and/or other such criteria as the Committee may determine. Upon the grant of Restricted Stock Units, the grantee
and the Company shall enter into an Award Agreement. The terms and conditions of each such Award Agreement shall be determined by the Committee and may differ among individual Awards and grantees. On or promptly following the vesting date or dates
applicable to any Restricted Stock Unit, but in no event later than March 15 of the year following the year in which such vesting occurs, such Restricted Stock Unit(s) shall be settled in the form of cash or shares of Stock, as specified in the
Award Agreement. Restricted Stock Units may not be sold, assigned, transferred, pledged, or otherwise encumbered or disposed of. 

(b)    Rights as a Stockholder. A grantee shall have the rights of a stockholder only as to Shares, if any, acquired
upon settlement of Restricted Stock Units. A grantee shall not be deemed to have acquired any such Shares unless and until the Restricted Stock Units shall have been settled in Shares pursuant to the terms of the Plan and the Award Agreement, the
Company shall have issued and delivered a certificate representing the Shares to the grantee (or transferred on the records of the Company with respect to uncertificated stock), and the grantee’s name has been entered in the books of the
Company as a stockholder. 
 (c)    Termination. Except as may otherwise be provided by the Committee either in
the Award Agreement or in writing after the Award Agreement is issued, a grantee’s right in all Restricted Stock Units that have not vested shall automatically terminate upon the grantee’s cessation of Service Relationship with the Company
and any Subsidiary for any reason. 
  

	SECTION 9.	 TRANSFER RESTRICTIONS; COMPANY RIGHT OF FIRST REFUSAL; COMPANY REPURCHASE RIGHTS 

(a)    Restrictions on Transfer. 

(i)    Non-Transferability of Stock Options. Stock Options and, prior to
exercise, the Shares issuable upon exercise of such Stock Option, shall not be transferable by the optionee otherwise than by will, or by the laws of descent and distribution, and all Stock Options shall be exercisable, during the optionee’s
lifetime, only by the optionee, or by the optionee’s legal representative or guardian in the event of the optionee’s incapacity. Notwithstanding the foregoing, the Committee, in its sole discretion, may provide in the Award Agreement
regarding a given Stock Option that the optionee may transfer by gift, without consideration for the transfer, 

  
 12 

 
his or her Non-Qualified Stock Options to his or her family members (as defined in Rule 701 of the Securities Act), to trusts for the benefit of such
family members, or to partnerships in which such family members are the only partners (to the extent such trusts or partnerships are considered “family members” for purposes of Rule 701 of the Securities Act), provided that the transferee
agrees in writing with the Company to be bound by all of the terms and conditions of this Plan and the applicable Award Agreement, including the execution of a stock power upon the issuance of Shares. Stock Options, and the Shares issuable upon
exercise of such Stock Options, shall be restricted as to any pledge, hypothecation, or other transfer, including any short position, any “put equivalent position” (as defined in the Exchange Act) or any “call equivalent
position” (as defined in the Exchange Act) prior to exercise. 
 (ii)    Shares. No Shares shall be sold,
assigned, transferred, pledged, hypothecated, given away or in any other manner disposed of or encumbered, whether voluntarily or by operation of law, unless (i) the transfer is in compliance with the terms of the applicable Award Agreement,
all applicable securities laws (including, without limitation, the Securities Act), and with the terms and conditions of this Section 9, (ii) the transfer does not cause the Company to become subject to the reporting requirements of the
Exchange Act, and (iii) the transferee consents in writing to be bound by the provisions of the Plan and the Award Agreement, including this Section 9. In connection with any proposed transfer, the Committee may require the transferor to
provide at the transferor’s own expense an opinion of counsel to the transferor, satisfactory to the Committee, that such transfer is in compliance with all foreign, federal and state securities laws (including, without limitation, the
Securities Act). Any attempted transfer of Shares not in accordance with the terms and conditions of this Section 9 shall be null and void, and the Company shall not reflect on its records any change in record ownership of any Shares as a
result of any such transfer, shall otherwise refuse to recognize any such transfer and shall not in any way give effect to any such transfer of Shares. The Company shall be entitled to seek protective orders, injunctive relief and other remedies
available at law or in equity including, without limitation, seeking specific performance or the rescission of any transfer not made in strict compliance with the provisions of this Section 9. Subject to the foregoing general provisions, and
unless otherwise provided in the applicable Award Agreement, Shares may be transferred pursuant to the following specific terms and conditions (provided that with respect to any transfer of Restricted Stock, all vesting and forfeiture provisions
shall continue to apply with respect to the original recipient): 
 (A)    Transfers to Permitted
Transferees. The Holder may transfer any or all of the Shares to one or more Permitted Transferees; provided, however, that following such transfer, such Shares shall continue to be subject to the terms of this Plan (including this
Section 9) and such Permitted Transferee(s) shall, as a condition to any such transfer, deliver a written acknowledgment to that effect to the Company and shall deliver a stock power to the Company with respect to the Shares. Notwithstanding
the foregoing, the Holder may not transfer any of the Shares to a Person whom the Company reasonably determines is a direct competitor or a potential competitor of the Company or any of its Subsidiaries. 

(B)    Transfers Upon Death. Upon the death of the Holder, any Shares then held by the Holder at the
time of such death and any Shares acquired after the Holder’s death by the Holder’s legal representative shall be subject to the provisions of this Plan, and the Holder’s estate, executors, administrators, personal representatives,
heirs, legatees and distributees shall be obligated to convey such Shares to the Company or its assigns under the terms contemplated by the Plan and the Award Agreement. 

  
 13 

 (b)    Right of First Refusal. In the event that a Holder desires
at any time to sell or otherwise transfer all or any part of his or her Shares (other than shares of Restricted Stock which by their terms are not transferrable), the Holder first shall give written notice to the Company of the Holder’s
intention to make such transfer. Such notice shall state the number of Shares that the Holder proposes to sell (the “Offered Shares”), the price and the terms at which the proposed sale is to be made and the name and address of the
proposed transferee. At any time within 30 days after the receipt of such notice by the Company, the Company or its assigns may elect to purchase all or any portion of the Offered Shares at the price and on the terms offered by the proposed
transferee and specified in the notice. The Company or its assigns shall exercise this right by mailing or delivering written notice to the Holder within the foregoing 30-day period. If the Company or its
assigns elect to exercise its purchase rights under this Section 9(b), the closing for such purchase shall, in any event, take place within 45 days after the receipt by the Company of the initial notice from the Holder. In the event that the
Company or its assigns do not elect to exercise such purchase right, or in the event that the Company or its assigns do not pay the full purchase price within such 45-day period, the Holder shall be required
to pay a transaction processing fee of $10,000 to the Company (unless waived by the Committee) and then may, within 60 days thereafter, sell the Offered Shares to the proposed transferee and at the same price and on the same terms as specified in
the Holder’s notice. Any Shares not sold to the proposed transferee shall remain subject to the Plan. If the Holder is a party to any stockholders agreements or other agreements with the Company and/or certain other of the Company’s
stockholders relating to the Shares, (i) the transferring Holder shall comply with the requirements of such stockholders agreements or other agreements relating to any proposed transfer of the Offered Shares, and (ii) any proposed
transferee that purchases Offered Shares shall enter into such stockholders agreements or other agreements with the Company and/or certain of the Company’s stockholders relating to the Offered Shares on the same terms and in the same capacity
as the transferring Holder. 
 (c)    Company’s Right of Repurchase. 

(i)    Right of Repurchase for Unvested Shares Issued Upon the Exercise of an Option. Upon a Termination Event, the
Company or its assigns shall have the right and option to repurchase from a Holder of Shares acquired upon exercise of a Stock Option which are still subject to a risk of forfeiture as of the Termination Event. Such repurchase rights may be
exercised by the Company within the later of (A) six months following the date of such Termination Event or (B) seven months after the acquisition of Shares upon exercise of a Stock Option. The repurchase price shall be equal to the lower
of the original per share price paid by the Holder, subject to adjustment as provided in Section 3(b) of the Plan, or the current Fair Market Value of such Shares as of the date the Company elects to exercise its repurchase rights. 

(ii)    Right of Repurchase With Respect to Restricted Stock. Upon a Termination Event, the Company or its assigns
shall have the right and option to repurchase from a Holder of Shares received pursuant to a Restricted Stock Award any Shares that are still subject to a risk of forfeiture as of the Termination Event. Such repurchase right may be exercised by the
Company within six months following the date of such Termination Event. The repurchase price shall be the lower of the original per share purchase price paid by the Holder, subject to adjustment as provided in Section 3(b) of the Plan, or the
current Fair Market Value of such Shares as of the date the Company elects to exercise its repurchase rights. 

  
 14 

 (iii)    Procedure. Any repurchase right of the Company shall be
exercised by the Company or its assigns by giving the Holder written notice on or before the last day of the repurchase period of its intention to exercise such repurchase right. Upon such notification, the Holder shall promptly surrender to the
Company, free and clear of any liens or encumbrances, any certificates representing the Shares being purchased, together with a duly executed stock power for the transfer of such Shares to the Company or the Company’s assignee or assignees.
Upon the Company’s or its assignee’s receipt of the certificates from the Holder, the Company or its assignee or assignees shall deliver to him, her or them a check for the applicable repurchase price; provided, however, that the
Company may pay the repurchase price by offsetting and canceling any indebtedness then owed by the Holder to the Company. 

(d)    Reserved. 

(e)    Escrow Arrangement. 

(i)    Escrow. In order to carry out the provisions of this Section 9 of this Plan more effectively, the
Company shall hold any Shares issued pursuant to Awards granted under the Plan in escrow together with separate stock powers executed by the Holder in blank for transfer. The Company shall not dispose of the Shares except as otherwise provided in
this Plan. In the event of any repurchase by the Company (or any of its assigns), the Company is hereby authorized by the Holder, as the Holder’s attorney-in-fact,
to date and complete the stock powers necessary for the transfer of the Shares being purchased and to transfer such Shares in accordance with the terms hereof. At such time as any Shares are no longer subject to the Company’s repurchase and
first refusal rights, the Company shall, at the written request of the Holder, deliver to the Holder a certificate representing such Shares with the balance of the Shares to be held in escrow pursuant to this Section. 

(ii)    Remedy. Without limitation of any other provision of this Plan or other rights, in the event that a Holder
or any other Person is required to sell a Holder’s Shares pursuant to the provisions of Sections 9(b) or (c) hereof and in the further event that he or she refuses or for any reason fails to deliver to the Company or its designated
purchaser of such Shares the certificate or certificates evidencing such Shares together with a related stock power, the Company or such designated purchaser may deposit the applicable purchase price for such Shares with a bank designated by the
Company, or with the Company’s independent public accounting firm, as agent or trustee, or in escrow, for such Holder or other Person, to be held by such bank or accounting firm for the benefit of and for delivery to him, her, them or it,
and/or, in its discretion, pay such purchase price by offsetting any indebtedness then owed by such Holder as provided above. Upon any such deposit and/or offset by the Company or its designated purchaser of such amount and upon notice to the Person
who was required to sell the Shares to be sold pursuant to the provisions of Sections 9(b) or (c), such Shares shall at such time be deemed to have been sold, assigned, transferred and conveyed to such purchaser, such Holder shall have no further
rights thereto (other than the right to withdraw the payment thereof held in escrow, if applicable), and the Company shall record such transfer in its stock transfer book or in any appropriate manner. 

  
 15 

 (f)    Lockup Provision. If requested by the Company, a Holder
shall not sell or otherwise transfer or dispose of any Shares (including, without limitation, pursuant to Rule 144 under the Securities Act) held by him or her for such period following the effective date of a public offering by the Company of
Shares as the Company shall specify reasonably and in good faith. If requested by the underwriter engaged by the Company, each Holder shall execute a separate letter confirming his or her agreement to comply with this Section. 

(g)    Adjustments for Changes in Capital Structure. If, as a result of any reorganization, recapitalization,
reclassification, stock dividend, stock split, reverse stock split or other similar change in the Common Stock, the outstanding Shares are increased or decreased or are exchanged for a different number or kind of securities of the Company, the
restrictions contained in this Section 9 shall apply with equal force to additional and/or substitute securities, if any, received by Holder in exchange for, or by virtue of his or her ownership of, Shares. 

(h)    Termination. The terms and provisions of Section 9(b) and Section 9(c) (except for the
Company’s right to repurchase Shares still subject to a risk of forfeiture upon a Termination Event) shall terminate upon the closing of the Company’s Initial Public Offering or upon consummation of any Sale Event, in either case as a
result of which Shares are registered under Section 12 of the Exchange Act and publicly-traded on any national security exchange. 
  

	SECTION 10.	 TAX WITHHOLDING 

(a)    Payment by Grantee. Each grantee shall, no later than the date as of which the value of an Award or of any
Shares or other amounts received thereunder first becomes includable in the gross income of the grantee for income tax purposes, pay to the Company, or make arrangements satisfactory to the Committee regarding payment of, any Federal, state, or
local taxes of any kind required by law to be withheld by the Company with respect to such income. The Company and any Subsidiary shall, to the extent permitted by law, have the right to deduct any such taxes from any payment of any kind otherwise
due to the grantee. The Company’s obligation to deliver stock certificates (or evidence of book entry) to any grantee is subject to and conditioned on any such tax withholding obligations being satisfied by the grantee. 

(b)    Payment in Stock. The Company’s minimum required tax withholding obligation may be satisfied, in whole
or in part, by the Company withholding from Shares to be issued pursuant to an Award a number of Shares having an aggregate Fair Market Value (as of the date the withholding is effected) that would satisfy the minimum withholding amount due. 

 

	SECTION 11.	 SECTION 409A AWARDS. 

To the extent that any Award is determined to constitute “nonqualified deferred compensation” within the meaning of Section 409A
(a “409A Award”), the Award shall be subject to such additional rules and requirements as may be specified by the Committee from time to time. In this regard, if any amount under a 409A Award is payable upon a “separation from
service” (within the meaning of Section 409A) to a grantee who is considered a “specified employee” (within the meaning of Section 409A), then no such payment shall be made prior to the date that is the earlier of
(i) six months and one day after the grantee’s separation from service, or (ii) the grantee’s death, but only to the extent such delay is necessary to prevent such payment from being

  
 16 

 
subject to interest, penalties and/or additional tax imposed pursuant to Section 409A. The Company makes no representation or warranty and shall have no liability to any grantee under the
Plan or any other Person with respect to any penalties or taxes under Section 409A that are, or may be, imposed with respect to any Award. 
  

	SECTION 12.	 AMENDMENTS AND TERMINATION 

The Board may, at any time, amend or discontinue the Plan and the Committee may, at any time, amend or cancel any outstanding Award for the
purpose of satisfying changes in law or for any other lawful purpose, but no such action shall adversely affect rights under any outstanding Award without the consent of the holder of the Award. The Committee may exercise its discretion to reduce
the exercise price of outstanding Stock Options or effect repricing through cancellation of outstanding Stock Options and by granting such holders new Awards in replacement of the cancelled Stock Options. To the extent determined by the Committee to
be required either by the Code to ensure that Incentive Stock Options granted under the Plan are qualified under Section 422 of the Code or otherwise, Plan amendments shall be subject to approval by the Company stockholders entitled to vote at
a meeting of stockholders. Nothing in this Section 12 shall limit the Board’s or Committee’s authority to take any action permitted pursuant to Section 3(c). The Board reserves the right to amend the Plan and/or the terms of any
outstanding Stock Options to the extent reasonably necessary to comply with the requirements of the exemption pursuant to paragraph (f)(4) of Rule 12h-1 of the Exchange Act. 

 

	SECTION 13.	 STATUS OF PLAN 

With respect to the portion of any Award that has not been exercised and any payments in cash, Stock or other consideration not received by a
grantee, a grantee shall have no rights greater than those of a general creditor of the Company unless the Committee shall otherwise expressly so determine in connection with any Award. 

 

	SECTION 14.	 GENERAL PROVISIONS 

(a)    No Distribution; Compliance with Legal Requirements. The Committee may require each person acquiring Shares
pursuant to an Award to represent to and agree with the Company in writing that such person is acquiring the Shares without a view to distribution thereof. No Shares shall be issued pursuant to an Award until all applicable securities law and other
legal and stock exchange or similar requirements have been satisfied. The Committee may require the placing of such stop-orders and restrictive legends on certificates for Stock and Awards as it deems appropriate. 

(b)    Delivery of Stock Certificates. Stock certificates to grantees under the Plan shall be deemed delivered for
all purposes when the Company or a stock transfer agent of the Company shall have mailed such certificates in the United States mail, addressed to the grantee, at the grantee’s last known address on file with the Company; provided that stock
certificates to be held in escrow pursuant to Section 9 of the Plan shall be deemed delivered when the Company shall have recorded the issuance in its records. Uncertificated Stock shall be deemed delivered for all purposes when the Company or
a stock transfer agent of the Company shall have given to the grantee by electronic mail (with proof of receipt) or by United States mail, addressed to the grantee, at the grantee’s last known address on file with the Company, notice of
issuance and recorded the issuance in its records (which may include electronic “book entry” records). 

  
 17 

 (c)    No Employment Rights. The adoption of the Plan and
the grant of Awards do not confer upon any Person any right to continued employment or Service Relationship with the Company or any Subsidiary. 

(d)    Trading Policy Restrictions. Option exercises and other Awards under the Plan shall be subject to the
Company’s insider trading policy-related restrictions, terms and conditions as may be established by the Committee, or in accordance with policies set by the Committee, from time to time. 

(e)    Designation of Beneficiary. Each grantee to whom an Award has been made under the Plan may designate a
beneficiary or beneficiaries to exercise any Award on or after the grantee’s death or receive any payment under any Award payable on or after the grantee’s death. Any such designation shall be on a form provided for that purpose by the
Committee and shall not be effective until received by the Committee. If no beneficiary has been designated by a deceased grantee, or if the designated beneficiaries have predeceased the grantee, the beneficiary shall be the grantee’s estate.

 (f)    Legend. Any certificate(s) representing the Shares shall carry substantially the following legend (and
with respect to uncertificated Stock, the book entries evidencing such shares shall contain the following notation): 
 The transferability
of this certificate and the shares of stock represented hereby are subject to the restrictions, terms and conditions (including repurchase and restrictions against transfers) contained in the Codiak BioSciences, Inc. 2015 Stock Option and
Grant Plan and any agreements entered into thereunder by and between the company and the holder of this certificate (a copy of which is available at the offices of the company for examination). 

(g)    Information to Holders of Options. In the event the Company is relying on the exemption from the registration
requirements of Section 12(g) of the Exchange Act contained in paragraph (f)(1) of Rule 12h-1 of the Exchange Act, the Company shall provide the information described in Rule 701(e)(3), (4) and
(5) of the Securities Act to all holders of Options in accordance with the requirements thereunder. The foregoing notwithstanding, the Company shall not be required to provide such information unless the optionholder has agreed in writing, on a
form prescribed by the Company, to keep such information confidential. 
  

	SECTION 15.	 EFFECTIVE DATE OF PLAN 

The Plan shall become effective upon adoption by the Board and shall be approved by stockholders in accordance with applicable state law and
the Company’s articles of incorporation and bylaws within 12 months thereafter. If the stockholders fail to approve the Plan within 12 months after its adoption by the Board of Directors, then any Awards granted or sold under the Plan shall be
rescinded and no additional grants or sales shall thereafter be made under the Plan. Subject to such approval by stockholders and to the requirement that no Shares may be issued 

  
 18 

 
hereunder prior to such approval, Stock Options and other Awards may be granted hereunder on and after adoption of the Plan by the Board. No grants of Stock Options and other Awards may be made
hereunder after the tenth anniversary of the date the Plan is adopted by the Board or the date the Plan is approved by the Company’s stockholders, whichever is earlier. 
  

	SECTION 16.	 GOVERNING LAW 

This Plan, all Awards and any controversy arising out of or relating to this Plan and all Awards shall be governed by and construed in
accordance with the General Corporation Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to
conflict of law principles that would result in the application of any law other than the law of the Commonwealth of Massachusetts. 
 DATE ADOPTED BY THE
BOARD OF DIRECTORS:    November 12, 2015 
 DATE APPROVED BY THE
STOCKHOLDERS:             November 12, 2015 

  
 19 

 CODIAK BIOSCIENCES, INC. 

AMENDMENT NO. 1 TO 

2015 STOCK OPTION AND GRANT PLAN 

WHEREAS, the Board of Directors and the stockholders of Codiak BioSciences, Inc. (the “Corporation”) approved and adopted the
2015 Stock Option and Grant Plan (the “Plan”) of the Corporation on November 11, 2015; 
 WHEREAS, the Board of
Directors and the stockholders of the Corporation have determined that it is in the best interest of the Corporation to amend the Plan as set forth in this Amendment. 

NOW, THEREFORE, the Plan is amended as follows: 
  

	1.	 Amendment of the 2015 Stock Option and Grant Plan 

1.01. Section 3(a) of the Plan is hereby amended and restated in its entirety to read as follows: 

“Stock Issuable. The maximum number of Shares reserved and available for issuance under the Plan shall be 17,000,000 Shares,
subject to adjustment as provided in Section 3(b). For purposes of this limitation, the Shares underlying any Awards that are forfeited, canceled, reacquired by the Company prior to vesting, satisfied without the issuance of Stock or
otherwise terminated (other than by exercise) and Shares that are withheld upon exercise of an Option or settlement of an Award to cover the exercise price or tax withholding shall be added back to the Shares available for issuance under the Plan.
Subject to such overall limitations, Shares may be issued up to such maximum number pursuant to any type or types of Award, and no more than 17,000,000 Shares may be issued pursuant to Incentive Stock Options. The Shares available for issuance under
the Plan may be authorized but unissued Shares or Shares reacquired by the Company. Beginning on the date that the Company becomes subject to Section 162(m) of the Code, Options with respect to no more than 17,000,000 Shares shall be granted to
any one individual in any calendar year period.” 
  

	2.	 Miscellaneous. 

2.01. Effect. Except as amended hereby, the Plan shall remain in full force and effect. 

2.02. Defined Terms. All capitalized terms used but not specifically defined herein shall have the same meanings given such terms
in the Plan unless the context clearly indicates or dictates a contrary meaning. 

 2.03. Governing Law. This Agreement shall be governed by and construed in
accordance with the General Corporation Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to
conflict of law principles that would result in the application of any law other than the law of the State of Massachusetts. 
  

			
	ADOPTED BY BOARD OF DIRECTORS:	  	February 18, 2016 & June 8, 2016
		
	APPROVED BY STOCKHOLDERS:	  	August 8, 2016

  
 2 

 CODIAK BIOSCIENCES, INC. 

AMENDMENT NO. 2 TO 

2015 STOCK OPTION AND GRANT PLAN 

WHEREAS, the Board of Directors and the stockholders of Codiak BioSciences, Inc. (the “Corporation”) approved and adopted the
2015 Stock Option and Grant Plan (the “Plan”) of the Corporation on November 12, 2015, which was amended on August 8, 2016; 

WHEREAS, the Board of Directors and the stockholders of the Corporation have determined that it is in the best interest of the Corporation to
amend the Plan as set forth in this Amendment. 
 NOW, THEREFORE, the Plan is amended as follows: 

 

	1.	 Amendment of the 2015 Stock Option and Grant Plan 

1.01. Section 3(a) of the Plan is hereby amended and restated in its entirety to read as follows: 

“Stock Issuable. The maximum number of Shares reserved and available for issuance under the Plan shall be 21,000,000 Shares,
subject to adjustment as provided in Section 3(b). For purposes of this limitation, the Shares underlying any Awards that are forfeited, canceled, reacquired by the Company prior to vesting, satisfied without the issuance of Stock or
otherwise terminated (other than by exercise) and Shares that are withheld upon exercise of an Option or settlement of an Award to cover the exercise price or tax withholding shall be added back to the Shares available for issuance under the Plan.
Subject to such overall limitations, Shares may be issued up to such maximum number pursuant to any type or types of Award, and no more than 21,000,000 Shares may be issued pursuant to Incentive Stock Options. The Shares available for issuance under
the Plan may be authorized but unissued Shares or Shares reacquired by the Company. Beginning on the date that the Company becomes subject to Section 162(m) of the Code, Options with respect to no more than 21,000,000 Shares shall be granted to
any one individual in any calendar year period.” 
  

	2.	 Miscellaneous. 

2.01. Effect. Except as amended hereby, the Plan shall remain in full force and effect. 

2.02. Defined Terms. All capitalized terms used but not specifically defined herein shall have the same meanings given such terms
in the Plan unless the context clearly indicates or dictates a contrary meaning. 

 2.03. Governing Law. This Agreement shall be governed by and construed in
accordance with the General Corporation Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to
conflict of law principles that would result in the application of any law other than the law of the Common Wealth of Massachusetts. 
  

			
	ADOPTED BY BOARD OF DIRECTORS:	  	January 22, 2018
		
	APPROVED BY STOCKHOLDERS:	  	June 5, 2018

  
 2 

 CODIAK BIOSCIENCES, INC. 

AMENDMENT NO. 3 TO 

2015 STOCK OPTION AND GRANT PLAN 

WHEREAS, the Board of Directors and the stockholders of Codiak BioSciences, Inc. (the “Corporation”) approved and adopted the
2015 Stock Option and Grant Plan (the “Plan”) of the Corporation on November 12, 2015, which was amended on August 8, 2016 and June 5, 2018; 

WHEREAS, the Board of Directors and the stockholders of the Corporation have determined that it is in the best interest of the Corporation to
amend the Plan as set forth in this Amendment. 
 NOW, THEREFORE, the Plan is amended as follows: 

 

	1.	 Amendment of the 2015 Stock Option and Grant Plan 

1.01. Section 3(a) of the Plan is hereby amended and restated in its entirety to read as follows: 

“Stock Issuable. The maximum number of Shares reserved and available for issuance under the Plan shall be 25,000,000 Shares,
subject to adjustment as provided in Section 3(b). For purposes of this limitation, the Shares underlying any Awards that are forfeited, canceled, reacquired by the Company prior to vesting, satisfied without the issuance of Stock or
otherwise terminated (other than by exercise) and Shares that are withheld upon exercise of an Option or settlement of an Award to cover the exercise price or tax withholding shall be added back to the Shares available for issuance under the Plan.
Subject to such overall limitations, Shares may be issued up to such maximum number pursuant to any type or types of Award, and no more than 25,000,000 Shares may be issued pursuant to Incentive Stock Options. The Shares available for issuance under
the Plan may be authorized but unissued Shares or Shares reacquired by the Company. Beginning on the date that the Company becomes subject to Section 162(m) of the Code, Options with respect to no more than 25,000,000 Shares shall be granted to
any one individual in any calendar year period.” 
  

	2.	 Miscellaneous. 

2.01. Effect. Except as amended hereby, the Plan shall remain in full force and effect. 

2.02. Defined Terms. All capitalized terms used but not specifically defined herein shall have the same meanings given such terms
in the Plan unless the context clearly indicates or dictates a contrary meaning. 

 2.03. Governing Law. This Agreement shall be governed by and construed in
accordance with the General Corporation Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to
conflict of law principles that would result in the application of any law other than the law of the Common Wealth of Massachusetts. 
  

			
	ADOPTED BY BOARD OF DIRECTORS:	  	October 4, 2018
		
	APPROVED BY STOCKHOLDERS:	  	October 9, 2018

  
 2 

 CODIAK BIOSCIENCES, INC. 

AMENDMENT NO. 4 TO 

2015 STOCK OPTION AND GRANT PLAN 

WHEREAS, the Board of Directors and the stockholders of Codiak BioSciences, Inc. (the “Corporation”) approved and adopted the
2015 Stock Option and Grant Plan (the “Plan”) of the Corporation on November 11, 2015; 
 WHEREAS, the Board of
Directors and the stockholders of the Corporation have determined that it is in the best interest of the Corporation to amend the Plan as set forth in this Amendment. 

NOW, THEREFORE, the Plan is amended as follows: 

1.    Amendment of the 2015 Stock Option and Grant Plan 

1.01.    Section 3(a) of the Plan is hereby amended and restated in its entirety to read as follows: 

“Stock Issuable. The maximum number of Shares reserved and available for issuance under the Plan shall be 30,500,000 Shares,
subject to adjustment as provided in Section 3(b). For purposes of this limitation, the Shares underlying any Awards that are forfeited, canceled, reacquired by the Company prior to vesting, satisfied without the issuance of Stock or
otherwise terminated (other than by exercise) and Shares that are withheld upon exercise of an Option or settlement of an Award to cover the exercise price or tax withholding shall be added back to the Shares available for issuance under the Plan.
Subject to such overall limitations, Shares may be issued up to such maximum number pursuant to any type or types of Award, and no more than 30,500,000 Shares may be issued pursuant to Incentive Stock Options. The Shares available for issuance
under the Plan may be authorized but unissued Shares or Shares reacquired by the Company. Beginning on the date that the Company becomes subject to Section 162(m) of the Code, Options with respect to no more than 30,500,000 Shares shall be
granted to any one individual in any calendar year period.” 
 2.    Miscellaneous. 

2.01.    Effect. Except as amended hereby, the Plan shall remain in full force and effect. 

2.02.    Defined Terms. All capitalized terms used but not specifically defined herein shall have the same
meanings given such terms in the Plan unless the context clearly indicates or dictates a contrary meaning. 

2.03.    Governing Law. This Agreement shall be governed by and construed in accordance with the General
Corporation Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to conflict of law principles that
would result in the application of any law other than the law of the Commonwealth of Massachusetts. 

 CODIAK BIOSCIENCES, INC. 

AMENDMENT NO. 5 TO 

2015 STOCK OPTION AND GRANT PLAN 

WHEREAS, the Board of Directors and the stockholders of Codiak BioSciences, Inc. (the “Company”) approved and adopted the
2015 Stock Option and Grant Plan (the “Plan”) of the Company on November 12, 2015, which was amended on August 8, 2016, June 5, 2018, October 4, 2018 and February 11, 2019; 

WHEREAS, the Board of Directors and the stockholders of the Company have determined that it is in the best interest of the Company and its
stockholders to amend the Plan as set forth in this Amendment No. 5 to 2015 Stock Option and Grant Plan (this “Amendment”). 

NOW, THEREFORE, the Plan is amended as follows: 
  

	1.	 Amendment of the 2015 Stock Option and Grant Plan 

1.01 The Plan is hereby amended by inserting the following language as Section 2(f): 

“Delegation of Authority to Grant Awards. Subject to applicable law, the Committee, in its discretion, may delegate to a committee
consisting of one or more officers of the Company including the Chief Executive Officer of the Company all or part of the Administrator’s authority and duties with respect to the granting of Awards to individuals who are not members of the
delegated committee.” 
 1.02. Section 3(a) of the Plan is hereby amended and restated in its entirety to read as follows:

 “Stock Issuable. The maximum number of Shares reserved and available for issuance under the Plan shall be 34,500,000 Shares,
subject to adjustment as provided in Section 3(b). For purposes of this limitation, the Shares underlying any Awards that are forfeited, canceled, reacquired by the Company prior to vesting, satisfied without the issuance of Stock or otherwise
terminated (other than by exercise) and Shares that are withheld upon exercise of an Option or settlement of an Award to cover the exercise price or tax withholding shall be added back to the Shares available for issuance under the Plan. Subject to
such overall limitations, Shares may be issued up to such maximum number pursuant to any type or types of Award, and no more than 34,500,000 Shares may be issued pursuant to Incentive Stock Options. The Shares available for issuance under the Plan
may be authorized but unissued Shares or Shares reacquired by the Company. Beginning on the date that the Company becomes subject to Section 162(m) of the Code, Options with respect to no more than 34,500,000 Shares shall be granted to any one
individual in any calendar year period.” 
  

	2.	 Miscellaneous. 

2.01. Effect. Except as amended hereby, the Plan shall remain in full force and effect. 

2.02. Defined Terms. All capitalized terms used but not specifically defined herein shall have the same meanings given such terms
in the Plan unless the context clearly indicates or dictates a contrary meaning. 

 2.03. Governing Law. This Agreement shall be governed by and construed in
accordance with the General Corporation Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to
conflict of law principles that would result in the application of any law other than the law of the Commonwealth of Massachusetts. 
  

			
	ADOPTED BY BOARD OF DIRECTORS:	  	July 29, 2019

  
 2 

 CODIAK BIOSCIENCES, INC. 

AMENDMENT NO. 6 TO 

2015 STOCK OPTION AND GRANT PLAN 

WHEREAS, the Board of Directors and the stockholders of Codiak BioSciences, Inc. (the “Company”) approved and adopted
the 2015 Stock Option and Grant Plan (the “Plan”) of the Company on November 12, 2015, which was amended on August 8, 2016, June 5, 2018, October 4, 2018, February 11, 2019 and July 29, 2019; 

WHEREAS, the Board of Directors and the stockholders of the Company have determined that it is in the best interest of the Company and
its stockholders to amend the Plan as set forth in this Amendment No. 6 to 2015 Stock Option and Grant Plan (this “Amendment”). 

NOW, THEREFORE, the Plan is amended as follows: 
  

	1.	 Amendment of the 2015 Stock Option and Grant Plan 

1.02. Section 3(a) of the Plan is hereby amended and restated in its entirety to read as follows: 

“Stock Issuable. The maximum number of Shares reserved and available for issuance under the Plan shall be 36,000,000 Shares,
subject to adjustment as provided in Section 3(b). For purposes of this limitation, the Shares underlying any Awards that are forfeited, canceled, reacquired by the Company prior to vesting, satisfied without the issuance of Stock or otherwise
terminated (other than by exercise) and Shares that are withheld upon exercise of an Option or settlement of an Award to cover the exercise price or tax withholding shall be added back to the Shares available for issuance under the Plan. Subject to
such overall limitations, Shares may be issued up to such maximum number pursuant to any type or types of Award, and no more than 36,000,000 Shares may be issued pursuant to Incentive Stock Options. The Shares available for issuance under the Plan
may be authorized but unissued Shares or Shares reacquired by the Company. Beginning on the date that the Company becomes subject to Section 162(m) of the Code, Options with respect to no more than 36,000,000 Shares shall be granted to any one
individual in any calendar year period.” 
  

	2.	 Miscellaneous. 

2.01. Effect. Except as amended hereby, the Plan shall remain in full force and effect. 

2.02. Defined Terms. All capitalized terms used but not specifically defined herein shall have the same meanings given such terms
in the Plan unless the context clearly indicates or dictates a contrary meaning. 

 2.03. Governing Law. This Agreement shall be governed by and construed in
accordance with the General Corporation Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to
conflict of law principles that would result in the application of any law other than the law of the Commonwealth of Massachusetts. 
  

			
	ADOPTED BY BOARD OF DIRECTORS:	  	January 15, 2020
		
	APPROVED BY STOCKHOLDERS:	  	March 5, 2020

  
 2 

 CODIAK BIOSCIENCES, INC. 

AMENDMENT NO. 7 TO 

2015 STOCK OPTION AND GRANT PLAN 

WHEREAS, the Board of Directors and the stockholders of Codiak BioSciences, Inc. (the “Company”) approved and adopted the
2015 Stock Option and Grant Plan (the “Plan”) of the Company on November 12, 2015, which was amended on August 8, 2016, June 5, 2018, October 4, 2018, February 11, 2019, July 29, 2019 and March 5, 2020; 

WHEREAS, the Board of Directors and the stockholders of the Company have determined that it is in the best interest of the Company and
its stockholders to amend the Plan as set forth in this Amendment No. 7 to 2015 Stock Option and Grant Plan (this “Amendment”). 

NOW, THEREFORE, the Plan is amended as follows: 
  

	1.	 Amendment of the 2015 Stock Option and Grant Plan 

1.02. Section 3(a) of the Plan is hereby amended and restated in its entirety to read as follows: 

“Stock Issuable. The maximum number of Shares reserved and available for issuance under the Plan shall be 38,500,000 Shares,
subject to adjustment as provided in Section 3(b). For purposes of this limitation, the Shares underlying any Awards that are forfeited, canceled, reacquired by the Company prior to vesting, satisfied without the issuance of Stock or otherwise
terminated (other than by exercise) and Shares that are withheld upon exercise of an Option or settlement of an Award to cover the exercise price or tax withholding shall be added back to the Shares available for issuance under the Plan. Subject to
such overall limitations, Shares may be issued up to such maximum number pursuant to any type or types of Award, and no more than 38,500,000 Shares may be issued pursuant to Incentive Stock Options. The Shares available for issuance under the Plan
may be authorized but unissued Shares or Shares reacquired by the Company.” 
  

	2.	 Miscellaneous. 

2.01. Effect. Except as amended hereby, the Plan shall remain in full force and effect. 

2.02. Defined Terms. All capitalized terms used but not specifically defined herein shall have the same meanings given such terms in
the Plan unless the context clearly indicates or dictates a contrary meaning. 
 2.03. Governing Law. This Agreement shall be
governed by and construed in accordance with the General Corporation Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of
Massachusetts, without regard to conflict of law principles that would result in the application of any law other than the law of the Commonwealth of Massachusetts. 

ADOPTED BY BOARD OF DIRECTORS: June 19, 2020 

APPROVED BY STOCKHOLDERS: October 2, 2020 

 INCENTIVE STOCK OPTION GRANT NOTICE 

UNDER THE CODIAK BIOSCIENCES, INC. 

2015 STOCK OPTION AND GRANT PLAN 

Pursuant to the Codiak BioSciences, Inc. 2015 Stock Option and Grant Plan (the “Plan”), Codiak BioSciences, Inc., a Delaware
corporation (together with any successor, the “Company”), has granted to the individual named below, an option (the “Stock Option”) to purchase on or prior to the Expiration Date, or such earlier date as is specified herein, all
or any part of the number of shares of Common Stock, par value $0.0001 per share (“Common Stock”), of the Company indicated below (the “Shares”), at the Option Exercise Price per share, subject to the terms and conditions set
forth in this Incentive Stock Option Grant Notice (the “Grant Notice”), the attached Incentive Stock Option Agreement (the “Agreement”) and the Plan. This Stock Option is intended to qualify as an “incentive stock
option” as defined in Section 422(b) of the Internal Revenue Code of 1986, as amended from time to time (the “Code”). To the extent that any portion of the Stock Option does not so qualify, it shall be deemed a non-qualified stock option. 
  

	 Name of Optionee: 
	__________________ (the “Optionee”) 

  

	 No. of Shares: 
	__________ Shares of Common Stock 

  

	 Grant Date: 
	__________________ 

  

	 Vesting Commencement Date: 
	__________________ (the “Vesting Commencement Date”) 

  

	 Expiration Date: 
	__________________ (the “Expiration Date”) 

  

	 Option Exercise Price/Share: 
	$_________________ (the “Option Exercise Price”) 

  

	 Vesting Schedule: 
	 25 percent of the Shares shall vest and become exercisable on the first anniversary of the Vesting Commencement Date; provided that the Optionee
continues to have a Service Relationship with the Company at such time. Thereafter, the remaining 75 percent of the Shares shall vest and become exercisable in equal quarterly installments over the following three (3) years, provided the
Optionee continues to have a Service Relationship with the Company on each vesting date. Notwithstanding anything in the Agreement to the contrary, in the case of a Sale Event, this Stock Option and the Shares shall be treated as provided in
Section 3(c) of the Plan[; provided, however, that if the Company is subject to a Change in Control, 50% of Optionee’s then unvested Shares shall vest immediately prior to the consummation of such Change in Control;
][provided, further, however, that if the Company is (a) subject to a Change in Control and (b) Optionee’s employment is terminated by the Company or successor corporation, as the case may be, without Cause, or
Optionee terminates her employment 

	 	 
for Good Reason, in either case, within ninety (90) days prior to the effective date of such Change in Control if the Company is in discussions with the potential acquirer, or within twelve
(12) months after the effective date of the Change in Control, then Optionee shall receive immediate acceleration of vesting of 100% of Optionee’s then unvested Shares. The terms “Change in Control”, “Cause” and
“Good Reason” have the meanings ascribed to them in the employment agreement dated [__], 201[_] by and between Optionee and the Company]. 

Attachments: Incentive Stock Option Agreement, 2015 Stock Option and Grant Plan 

  
 2 

 INCENTIVE STOCK OPTION AGREEMENT 

UNDER THE CODIAK BIOSCIENCES, INC. 

2015 STOCK OPTION AND GRANT PLAN 

All capitalized terms used herein and not otherwise defined shall have the respective meanings set forth in the Grant Notice and the Plan.

 1.    Vesting, Exercisability and Termination. 

(a)    No portion of this Stock Option may be exercised until such portion shall have vested and become exercisable. 

(b)    Except as set forth below, and subject to the determination of the Committee in its sole discretion to accelerate
the vesting schedule hereunder, this Stock Option shall be vested and exercisable on the respective dates indicated below: 

(i)    This Stock Option shall initially be unvested and unexercisable. 

(ii)    This Stock Option shall vest and become exercisable in accordance with the Vesting Schedule set
forth in the Grant Notice. 
 (c)    Termination. Except as may otherwise be provided by the Committee, if the
Optionee’s Service Relationship is terminated, the period within which to exercise this Stock Option will be subject to earlier termination as set forth below (and if not exercised within such period, shall thereafter terminate subject, in each
case, to Section 3(c) of the Plan): 
 (i)    Termination Due to Death or Disability. If the
Optionee’s Service Relationship terminates by reason of such Optionee’s death or Disability, this Stock Option may be exercised, to the extent exercisable on the date of such termination, by the Optionee, the Optionee’s legal
representative or legatee for a period of 12 months from the date of death or Disability or until the Expiration Date, if earlier. 

(ii)    Other Termination. If the Optionee’s Service Relationship terminates for any reason
other than death or Disability, and unless otherwise determined by the Committee, this Stock Option may be exercised, to the extent exercisable on the date of termination, for a period of 90 days from the date of termination or until the Expiration
Date, if earlier; provided however, if the Optionee’s Service Relationship is terminated for Cause, this Stock Option shall terminate immediately upon the date of such termination. 

For purposes hereof, the Committee’s determination of the reason for termination of the Optionee’s Service Relationship shall be
conclusive and binding on the Optionee and his or her representatives or legatees. Any portion of this Stock Option that is not vested and exercisable on the date of termination of the Service Relationship shall terminate immediately and be null and
void. 

  
 3 

 (d)    It is understood and intended that this Stock Option is intended
to qualify as an “incentive stock option” as defined in Section 422 of the Code to the extent permitted under applicable law. Accordingly, the Optionee understands that in order to obtain the benefits of an incentive stock option
under Section 422 of the Code, no sale or other disposition may be made of Shares for which incentive stock option treatment is desired within the one-year period beginning on the day after the day of the
transfer of such Shares to him or her, nor within the two-year period beginning on the day after Grant Date of this Stock Option and further that this Stock Option must be exercised within three months after
termination of employment as an employee (or 12 months in the case of death or disability) to qualify as an incentive stock option. If the Optionee disposes (whether by sale, gift, transfer or otherwise) of any such Shares within either of these
periods, he or she will notify the Company within 30 days after such disposition. The Optionee also agrees to provide the Company with any information concerning any such dispositions required by the Company for tax purposes. Further, to the extent
this Stock Option and any other incentive stock options of the Optionee having an aggregate Fair Market Value in excess of $100,000 (determined as of the Grant Date) first become exercisable in any year, such options will not qualify as incentive
stock options. 
 2.    Exercise of Stock Option. 

(a)    The Optionee may exercise this Stock Option only in the following manner: Prior to the Expiration Date, the Optionee
may deliver a Stock Option exercise notice (an “Exercise Notice”) in the form of Appendix A hereto indicating his or her election to purchase some or all of the Shares with respect to which this Stock Option is
then exercisable. Such notice shall specify the number of Shares to be purchased. Payment of the purchase price may be made by one or more of the methods described in Section 5 of the Plan, subject to the limitations contained in such Section
of the Plan, including the requirement that the Committee specifically approve in advance certain payment methods. 

(b)    Notwithstanding any other provision hereof or of the Plan, no portion of this Stock Option shall be exercisable
after the Expiration Date. 
 3.    Incorporation of Plan. Notwithstanding anything herein to the contrary, this
Stock Option shall be subject to and governed by all the terms and conditions of the Plan. 
 4.    Transferability
of Stock Option. This Stock Option is personal to the Optionee and is not transferable by the Optionee in any manner other than by will or by the laws of descent and distribution. The Stock Option may be exercised during the Optionee’s
lifetime only by the Optionee (or by the Optionee’s guardian or personal representative in the event of the Optionee’s incapacity). The Optionee may elect to designate a beneficiary by providing written notice of the name of such
beneficiary to the Company, and may revoke or change such designation at any time by filing written notice of revocation or change with the Company; such beneficiary may exercise the Optionee’s Stock Option in the event of the Optionee’s
death to the extent provided herein. If the Optionee does not designate a beneficiary, or if the designated beneficiary predeceases the Optionee, the legal representative of the Optionee may exercise this Stock Option to the extent provided herein
in the event of the Optionee’s death. 

  
 4 

 5.    Restrictions on Transfer of Shares. The Shares acquired
upon exercise of the Stock Option shall be subject to certain transfer restrictions and other limitations including, without limitation, the provisions contained in Section 9 of the Plan. 

6.    Miscellaneous Provisions. 

(a)    Equitable Relief. The parties hereto agree and declare that legal remedies may be inadequate to enforce the
provisions of this Agreement and that equitable relief, including specific performance and injunctive relief, may be used to enforce the provisions of this Agreement. 

(b)    Adjustments for Changes in Capital Structure. If, as a result of any reorganization, recapitalization,
reincorporation, reclassification, stock dividend, stock split, reverse stock split or other similar change in the Common Stock, the outstanding shares of Common Stock are increased or decreased or are exchanged for a different number or kind of
securities of the Company, the restrictions contained in this Agreement shall apply with equal force to additional and/or substitute securities, if any, received by the Optionee in exchange for, or by virtue of his or her ownership of, this Stock
Option or Shares acquired pursuant thereto. 
 (c)    Change and Modifications. This Agreement may not be orally
changed, modified or terminated, nor shall any oral waiver of any of its terms be effective. This Agreement may be changed, modified or terminated only by an agreement in writing signed by the Company and the Optionee. 

(d)    Governing Law. This Agreement shall be governed by and construed in accordance with the General Corporation
Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to conflict of law principles that would result
in the application of any law other than the law of the Commonwealth of Massachusetts. 
 (e)    Headings. The
headings are intended only for convenience in finding the subject matter and do not constitute part of the text of this Agreement and shall not be considered in the interpretation of this Agreement. 

(f)    Saving Clause. If any provision(s) of this Agreement shall be determined to be illegal or unenforceable, such
determination shall in no manner affect the legality or enforceability of any other provision hereof. 

(g)    Notices. All notices, requests, consents and other communications shall be in writing and be deemed given
when delivered personally, by telex or facsimile transmission or when received if mailed by first class registered or certified mail, postage prepaid. Notices to the Company or the Optionee shall be addressed as set forth underneath their signatures
below, or to such other address or addresses as may have been furnished by such party in writing to the other. 

(h)    Benefit and Binding Effect. This Agreement shall be binding upon and shall inure to the benefit of the
parties hereto, their respective successors, assigns, and legal representatives. The Company has the right to assign this Agreement, and such assignee shall become entitled to all the rights of the Company hereunder to the extent of such assignment.

  
 5 

 (i)    Counterparts. For the convenience of the parties and to
facilitate execution, this Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which shall constitute one and the same document. 

(j)    Integration. This Agreement constitutes the entire agreement between the parties with respect to this Stock
Option and supersedes all prior agreements and discussions between the parties concerning such subject matter. 

7.    Dispute Resolution. 

(a)    Except as provided below, any dispute arising out of or relating to the Plan or this Stock Option, this Agreement,
or the breach, termination or validity of the Plan, this Stock Option or this Agreement, shall be finally settled by binding arbitration conducted expeditiously in accordance with the J.A.M.S./Endispute Comprehensive Arbitration Rules and Procedures
(the “J.A.M.S. Rules”). The arbitration shall be governed by the United States Arbitration Act, 9 U.S.C. Sections 1 16, and judgment upon the award rendered by the arbitrators may be entered by any court having jurisdiction thereof. The
place of arbitration shall be Massachusetts. 
 (b)    The arbitration shall commence within 60 days of the date on which
a written demand for arbitration is filed by any party hereto. In connection with the arbitration proceeding, the arbitrator shall have the power to order the production of documents by each party and any third-party witnesses. In addition, each
party may take up to three depositions as of right, and the arbitrator may in his or her discretion allow additional depositions upon good cause shown by the moving party. However, the arbitrator shall not have the power to order the answering of
interrogatories or the response to requests for admission. In connection with any arbitration, each party to the arbitration shall provide to the other, no later than seven business days before the date of the arbitration, the identity of all
persons that may testify at the arbitration and a copy of all documents that may be introduced at the arbitration or considered or used by a party’s witness or expert. The arbitrator’s decision and award shall be made and delivered within
six months of the selection of the arbitrator. The arbitrator’s decision shall set forth a reasoned basis for any award of damages or finding of liability. The arbitrator shall not have power to award damages in excess of actual compensatory
damages and shall not multiply actual damages or award punitive damages, and each party hereby irrevocably waives any claim to such damages. 

(c)    The Company, the Optionee, each party to the Agreement and any other holder of Shares issued pursuant to this
Agreement (each, a “Party”) covenants and agrees that such party will participate in the arbitration in good faith. This Section 7 applies equally to requests for temporary, preliminary or permanent injunctive relief, except that in
the case of temporary or preliminary injunctive relief any party may proceed in court without prior arbitration for the limited purpose of avoiding immediate and irreparable harm. 

(d)    Each Party (i) hereby irrevocably submits to the jurisdiction of any United States District Court of competent
jurisdiction for the purpose of enforcing the award or decision 

  
 6 

 
in any such proceeding, (ii) hereby waives, and agrees not to assert, by way of motion, as a defense, or otherwise, in any such suit, action or proceeding, any claim that it is not subject
personally to the jurisdiction of the above named courts, that its property is exempt or immune from attachment or execution (except as protected by applicable law), that the suit, action or proceeding is brought in an inconvenient forum, that the
venue of the suit, action or proceeding is improper or that this Agreement or the subject matter hereof may not be enforced in or by such court, and (iii) hereby waives and agrees not to seek any review by any court of any other jurisdiction
which may be called upon to grant an enforcement of the judgment of any such court. Each Party hereby consents to service of process by registered mail at the address to which notices are to be given. Each Party agrees that its, his or her
submission to jurisdiction and its, his or her consent to service of process by mail is made for the express benefit of each other Party. Final judgment against any Party in any such action, suit or proceeding may be enforced in other jurisdictions
by suit, action or proceeding on the judgment, or in any other manner provided by or pursuant to the laws of such other jurisdiction. 

[SIGNATURE PAGE FOLLOWS] 

  
 7 

 The foregoing Agreement is hereby accepted and the terms and conditions thereof hereby
agreed to by the undersigned as of the date first above written. 
  

			
	CODIAK BIOSCIENCES, INC.
		
	By:	 	 
		 	Name: Doug Williams
		 	Title: President and Chief Executive Officer
	
	 Address:
  

500 Technology Square, 9th Floor

 
 Cambridge, MA 02139

 The undersigned hereby acknowledges receiving and reviewing a copy of the Plan, including, without limitation,
Section 9 thereof, and understands that this Stock Option is subject to the terms of the Plan and of this Agreement. This Agreement is hereby accepted, and the terms and conditions of the Plan, the Grant Notice and this Agreement, SPECIFICALLY
INCLUDING THE ARBITRATION PROVISIONS SET FORTH IN SECTION 7 OF THIS AGREEMENT, are hereby agreed to, by the undersigned as of the date first above written. 
  

	
	OPTIONEE:
	
	   

	Name:
	
	Address:
	
	   

	
	   

	
	   

  
 8 

 
	
	DESIGNATED BENEFICIARY:
	
	   

	
	Beneficiary’s Address:
	
	   

	
	   

	
	   

  
 9 

 Appendix A 

STOCK OPTION EXERCISE NOTICE 
 Codiak
BioSciences, Inc. 
 Attention: ______ 
 ______________ 

______________ 
 Pursuant to the terms of the
grant notice and stock option agreement between the undersigned and Codiak BioSciences, Inc. (the “Company”) dated __________ (the “Agreement”) under the Codiak BioSciences, Inc. 2015 Stock Option and Grant Plan, I,
[Insert Name] ________________, hereby [Circle One] partially/fully exercise such option by including herein payment in the amount of $______ representing the purchase price for [Fill in number of Shares] _______ Shares. I have chosen the following
form(s) of payment: 
  

							
		 	[  ]	  	1.	  	Cash
		 	[  ]	  	2.	  	Certified or bank check payable to Codiak BioSciences, Inc.
		 	[  ]	  	3.	  	Other (as referenced in the Agreement and described in the Plan (please describe))
		 		  		  	______________________________________________________.

 In connection with my exercise of the option as set forth above, I hereby represent and warrant to the Company
as follows: 
 (i)    I am purchasing the Shares for my own account for investment only, and not for
resale or with a view to the distribution thereof. 
 (ii)    I have had such an opportunity as I have
deemed adequate to obtain from the Company such information as is necessary to permit me to evaluate the merits and risks of my investment in the Company and have consulted with my own advisers with respect to my investment in the Company. 

(iii)    I have sufficient experience in business, financial and investment matters to be able to evaluate
the risks involved in the purchase of the Shares and to make an informed investment decision with respect to such purchase. 

(iv)    I can afford a complete loss of the value of the Shares and am able to bear the economic risk of
holding such Shares for an indefinite period of time. 
 (v)    I understand that the Shares may not be
registered under the Securities Act of 1933 (it being understood that the Shares are being issued and sold in reliance on the exemption provided in Rule 701 thereunder) or any applicable state securities or “blue sky” laws and may not be
sold or otherwise transferred or disposed of in the absence of an effective registration statement under the Securities Act of 1933 and under any applicable state securities or “blue sky” laws (or exemptions from the registration
requirement thereof). I further acknowledge that certificates representing Shares will bear restrictive legends reflecting the foregoing and/or that book entries for uncertificated Shares will include similar restrictive notations. 

  
 10 

 (vi)    I have read and understand the Plan and
acknowledge and agree that the Shares are subject to all of the relevant terms of the Plan, including without limitation, the transfer restrictions set forth in Section 9 of the Plan. 

(vii)    I understand and agree that the Company has a right of first refusal with respect to the Shares
pursuant to Section 9(b) of the Plan. 
 (viii)    I understand and agree that the Company has
certain repurchase rights with respect to the Shares pursuant to Section 9(c) of the Plan. 

(ix)    I understand and agree that I may not sell or otherwise transfer or dispose of the Shares for a
period of time following the effective date of a public offering by the Company as described in Section 9(f) of the Plan. 
  

			
	Sincerely yours,
	
	 
	Name:
	
	Address:
	
	 
	
	 
	
	 
		
	Date:	 	 

  
 11 

 NON-QUALIFIED STOCK OPTION GRANT NOTICE 

UNDER THE CODIAK BIOSCIENCES, INC. 

2015 STOCK OPTION AND GRANT PLAN 

Pursuant to the Codiak BioSciences, Inc. 2015 Stock Option and Grant Plan (the “Plan”), Codiak BioSciences, Inc., a Delaware
corporation (together with any successor, the “Company”), has granted to the individual named below, an option (the “Stock Option”) to purchase on or prior to the Expiration Date, or such earlier date as is specified herein, all
or any part of the number of shares of Common Stock, par value $0.0001 per share (“Common Stock”), of the Company indicated below (the “Shares”), at the Option Exercise Price per share, subject to the terms and conditions set
forth in this Non-Qualified Stock Option Grant Notice (the “Grant Notice”), the attached Non-Qualified Stock Option Agreement (the “Agreement”) and
the Plan. This Stock Option is not intended to qualify as an “incentive stock option” as defined in Section 422(b) of the Internal Revenue Code of 1986, as amended from time to time (the “Code”). 

 

	 Name of Optionee: 
	__________________ (the “Optionee”) 

  

	 No. of Shares: 
	__________ Shares of Common Stock 

  

	 Grant Date: 
	__________________ 

  

	 Vesting Commencement Date: 
	__________________ (the “Vesting Commencement Date”) 

  

	 Expiration Date: 
	__________________ (the “Expiration Date”) 

  

	 Option Exercise Price/Share: 
	$_________________ (the “Option Exercise Price”) 

  

	 Vesting Schedule: 
	 25 percent of the Shares shall vest and become exercisable on the first anniversary of the Vesting Commencement Date; provided that the Optionee
continues to have a Service Relationship with the Company at such time. Thereafter, the remaining 75 percent of the Shares shall vest and become exercisable in equal quarterly installments over the following three (3), provided the Optionee
continues to have a Service Relationship with the Company on each vesting date. Notwithstanding anything in the Agreement to the contrary, in the case of a Sale Event, this Stock Option and the Shares shall be treated as provided in
Section 3(c) of the Plan[; provided, however, that if the Company is subject to a Change in Control, 50% of Optionee’s then unvested Shares shall vest immediately prior to the consummation of such Change in Control;
][provided, further, however, that if the Company is (a) subject to a Change in Control and (b) Optionee’s employment is terminated by the Company or successor corporation, as the case may be, without Cause, or
Optionee terminates her employment for Good Reason, in either case, within ninety (90) days prior to 

	 	 
the effective date of such Change in Control if the Company is in discussions with the potential acquirer, or within twelve (12) months after the effective date of the Change in Control,
then Optionee shall receive immediate acceleration of vesting of 100% of Optionee’s then unvested Shares. The terms “Change in Control”, “Cause” and “Good Reason” have the meanings ascribed to them in the
employment agreement dated [__], 201[_] by and between Optionee and the Company]. 

 Attachments:
Non-Qualified Stock Option Agreement, 2015 Stock Option and Grant Plan 

  
 2 

 NON-QUALIFIED STOCK OPTION AGREEMENT 

UNDER THE CODIAK BIOSCIENCES, INC. 

2015 STOCK OPTION AND GRANT PLAN 

All capitalized terms used herein and not otherwise defined shall have the respective meanings set forth in the Grant Notice and the Plan.

 1.    Vesting, Exercisability and Termination. 

(a)    No portion of this Stock Option may be exercised until such portion shall have vested and become exercisable. 

(b)    Except as set forth below, and subject to the determination of the Committee in its sole discretion to accelerate
the vesting schedule hereunder, this Stock Option shall be vested and exercisable on the respective dates indicated below: 

(i)    This Stock Option shall initially be unvested and unexercisable. 

(ii)    This Stock Option shall vest and become exercisable in accordance with the Vesting Schedule set
forth in the Grant Notice. 
 (c)    Termination. Except as may otherwise be provided by the Committee, if the
Optionee’s Service Relationship is terminated, the period within which to exercise this Stock Option will be subject to earlier termination as set forth below (and if not exercised within such period, shall thereafter terminate subject, in each
case, to Section 3(c) of the Plan): 
 (i)    Termination Due to Death or Disability. If the
Optionee’s Service Relationship terminates by reason of such Optionee’s death or Disability, this Stock Option may be exercised, to the extent exercisable on the date of such termination, by the Optionee, the Optionee’s legal
representative or legatee for a period of 12 months from the date of death or Disability or until the Expiration Date, if earlier. 

(ii)    Other Termination. If the Optionee’s Service Relationship terminates for any reason
other than death or Disability, and unless otherwise determined by the Committee, this Stock Option may be exercised, to the extent exercisable on the date of termination, for a period of 90 days from the date of termination or until the Expiration
Date, if earlier; provided however, if the Optionee’s Service Relationship is terminated for Cause, this Stock Option shall terminate immediately upon the date of such termination. 

For purposes hereof, the Committee’s determination of the reason for termination of the Optionee’s Service Relationship shall be
conclusive and binding on the Optionee and his or her representatives or legatees and any Permitted Transferee. Any portion of this Stock Option that is not vested and exercisable on the date of termination of the Service Relationship shall
terminate immediately and be null and void. 

  
 3 

 2.    Exercise of Stock Option. 

(a)    The Optionee may exercise this Stock Option only in the following manner: Prior to the Expiration Date, the Optionee
may deliver a Stock Option exercise notice (an “Exercise Notice”) in the form of Appendix A hereto indicating his or her election to purchase some or all of the Shares with respect to which this Stock Option is
then exercisable. Such notice shall specify the number of Shares to be purchased. Payment of the purchase price may be made by one or more of the methods described in Section 5 of the Plan, subject to the limitations contained in such Section
of the Plan, including the requirement that the Committee specifically approve in advance certain payment methods. 

(b)    Notwithstanding any other provision hereof or of the Plan, no portion of this Stock Option shall be exercisable
after the Expiration Date. 
 3.    Incorporation of Plan. Notwithstanding anything herein to the contrary, this
Stock Option shall be subject to and governed by all the terms and conditions of the Plan. 
 4.    Transferability
of Stock Option. This Stock Option is personal to the Optionee and is not transferable by the Optionee in any manner other than by will or by the laws of descent and distribution. The Stock Option may be exercised during the Optionee’s
lifetime only by the Optionee (or by the Optionee’s guardian or personal representative in the event of the Optionee’s incapacity). The Optionee may elect to designate a beneficiary by providing written notice of the name of such
beneficiary to the Company, and may revoke or change such designation at any time by filing written notice of revocation or change with the Company; such beneficiary may exercise the Optionee’s Stock Option in the event of the Optionee’s
death to the extent provided herein. If the Optionee does not designate a beneficiary, or if the designated beneficiary predeceases the Optionee, the legal representative of the Optionee may exercise this Stock Option to the extent provided herein
in the event of the Optionee’s death. 
 5.    Restrictions on Transfer of Shares. The Shares acquired upon
exercise of the Stock Option shall be subject to certain transfer restrictions and other limitations including, without limitation, the provisions contained in Section 9 of the Plan. 

6.    Miscellaneous Provisions. 

(a)    Equitable Relief. The parties hereto agree and declare that legal remedies may be inadequate to enforce the
provisions of this Agreement and that equitable relief, including specific performance and injunctive relief, may be used to enforce the provisions of this Agreement. 

(b)    Adjustments for Changes in Capital Structure. If, as a result of any reorganization, recapitalization,
reincorporation, reclassification, stock dividend, stock split, reverse stock split or other similar change in the Common Stock, the outstanding shares of Common Stock are increased or decreased or are exchanged for a different number or kind of
securities of the Company, the restrictions contained in this Agreement shall apply with equal force to additional and/or substitute securities, if any, received by the Optionee in exchange for, or by virtue of his or her ownership of, this Stock
Option or Shares acquired pursuant thereto. 

  
 4 

 (c)    Change and Modifications. This Agreement may not be orally
changed, modified or terminated, nor shall any oral waiver of any of its terms be effective. This Agreement may be changed, modified or terminated only by an agreement in writing signed by the Company and the Optionee. 

(d)    Governing Law. This Agreement shall be governed by and construed in accordance with the General Corporation
Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to conflict of law principles that would result
in the application of any law other than the law of the Commonwealth of Massachusetts. 
 (e)    Headings. The
headings are intended only for convenience in finding the subject matter and do not constitute part of the text of this Agreement and shall not be considered in the interpretation of this Agreement. 

(f)    Saving Clause. If any provision(s) of this Agreement shall be determined to be illegal or unenforceable, such
determination shall in no manner affect the legality or enforceability of any other provision hereof. 

(g)    Notices. All notices, requests, consents and other communications shall be in writing and be deemed given
when delivered personally, by telex or facsimile transmission or when received if mailed by first class registered or certified mail, postage prepaid. Notices to the Company or the Optionee shall be addressed as set forth underneath their signatures
below, or to such other address or addresses as may have been furnished by such party in writing to the other. 

(h)    Benefit and Binding Effect. This Agreement shall be binding upon and shall inure to the benefit of the
parties hereto, their respective successors, assigns, and legal representatives. The Company has the right to assign this Agreement, and such assignee shall become entitled to all the rights of the Company hereunder to the extent of such assignment.

 (i)    Counterparts. For the convenience of the parties and to facilitate execution, this Agreement may be
executed in two or more counterparts, each of which shall be deemed an original, but all of which shall constitute one and the same document. 

(j)    Integration. This Agreement constitutes the entire agreement between the parties with respect to this Stock
Option and supersedes all prior agreements and discussions between the parties concerning such subject matter. 

7.    Dispute Resolution. 

(a)    Except as provided below, any dispute arising out of or relating to the Plan or this Stock Option, this Agreement,
or the breach, termination or validity of the Plan, this Stock Option or this Agreement, shall be finally settled by binding arbitration conducted expeditiously in accordance with the J.A.M.S./Endispute Comprehensive Arbitration Rules and Procedures
(the “J.A.M.S. Rules”). The arbitration shall be governed by the United States Arbitration Act, 9 U.S.C. Sections 1-16, and judgment upon the award rendered by the arbitrators may be entered by any
court having jurisdiction thereof. The place of arbitration shall be Massachusetts. 

  
 5 

 (b)    The arbitration shall commence within 60 days of the date on
which a written demand for arbitration is filed by any party hereto. In connection with the arbitration proceeding, the arbitrator shall have the power to order the production of documents by each party and any third-party witnesses. In addition,
each party may take up to three depositions as of right, and the arbitrator may in his or her discretion allow additional depositions upon good cause shown by the moving party. However, the arbitrator shall not have the power to order the answering
of interrogatories or the response to requests for admission. In connection with any arbitration, each party to the arbitration shall provide to the other, no later than seven business days before the date of the arbitration, the identity of all
persons that may testify at the arbitration and a copy of all documents that may be introduced at the arbitration or considered or used by a party’s witness or expert. The arbitrator’s decision and award shall be made and delivered within
six months of the selection of the arbitrator. The arbitrator’s decision shall set forth a reasoned basis for any award of damages or finding of liability. The arbitrator shall not have power to award damages in excess of actual compensatory
damages and shall not multiply actual damages or award punitive damages, and each party hereby irrevocably waives any claim to such damages. 

(c)    The Company, the Optionee, each party to the Agreement and any other holder of Shares issued pursuant to this
Agreement (each, a “Party”) covenants and agrees that such party will participate in the arbitration in good faith. This Section 7 applies equally to requests for temporary, preliminary or permanent injunctive relief, except that in
the case of temporary or preliminary injunctive relief any party may proceed in court without prior arbitration for the limited purpose of avoiding immediate and irreparable harm. 

(d)    Each Party (i) hereby irrevocably submits to the jurisdiction of any United States District Court of competent
jurisdiction for the purpose of enforcing the award or decision in any such proceeding, (ii) hereby waives, and agrees not to assert, by way of motion, as a defense, or otherwise, in any such suit, action or proceeding, any claim that it is not
subject personally to the jurisdiction of the above named courts, that its property is exempt or immune from attachment or execution (except as protected by applicable law), that the suit, action or proceeding is brought in an inconvenient forum,
that the venue of the suit, action or proceeding is improper or that this Agreement or the subject matter hereof may not be enforced in or by such court, and (iii) hereby waives and agrees not to seek any review by any court of any other
jurisdiction which may be called upon to grant an enforcement of the judgment of any such court. Each Party hereby consents to service of process by registered mail at the address to which notices are to be given. Each Party agrees that its, his or
her submission to jurisdiction and its, his or her consent to service of process by mail is made for the express benefit of each other Party. Final judgment against any Party in any such action, suit or proceeding may be enforced in other
jurisdictions by suit, action or proceeding on the judgment, or in any other manner provided by or pursuant to the laws of such other jurisdiction. 

[SIGNATURE PAGE FOLLOWS] 

  
 6 

 The foregoing Agreement is hereby accepted and the terms and conditions thereof hereby
agreed to by the undersigned as of the date first above written. 
  

			
	CODIAK BIOSCIENCES, INC.
		
	By:	 	 
		 	Name: Doug Williams
		 	Title: President and Chief Executive Officer
	
	 Address:
  

500 Technology Square, 9th Floor

 
 Cambridge, MA 02139

 The undersigned hereby acknowledges receiving and reviewing a copy of the Plan, including, without limitation,
Section 9 thereof, and understands that this Stock Option is subject to the terms of the Plan and of this Agreement. This Agreement is hereby accepted, and the terms and conditions of the Plan, the Grant Notice and this Agreement, SPECIFICALLY
INCLUDING THE ARBITRATION PROVISIONS SET FORTH IN SECTION 7 OF THIS AGREEMENT, are hereby agreed to, by the undersigned as of the date first above written. 
  

	
	OPTIONEE:
	
	   

	Name:
	
	Address:
	
	   

	
	   

	
	   

  
 7 

 
	
	DESIGNATED BENEFICIARY:
	
	   

	
	Beneficiary’s Address:
	
	   

	
	   

	
	   

  
 8 

 Appendix A 

STOCK OPTION EXERCISE NOTICE 
 Codiak
BioSciences, Inc. 
 Attention: ______ 
 ______________ 

______________ 
 Pursuant to the terms of the
grant notice and stock option agreement between the undersigned and Codiak BioSciences, Inc. (the “Company”) dated __________ (the “Agreement”) under the Codiak BioSciences, Inc. 2015 Stock Option and Grant Plan, I,
[Insert Name] ________________, hereby [Circle One] partially/fully exercise such option by including herein payment in the amount of $______ representing the purchase price for [Fill in number of Shares] _______ Shares. I have chosen the following
form(s) of payment: 
  

							
		 	[  ]	  	1.	  	Cash
		 	[  ]	  	2.	  	Certified or bank check payable to Codiak BioSciences, Inc.
		 	[  ]	  	3.	  	Other (as referenced in the Agreement and described in the Plan (please describe))
		 		  		  	______________________________________________________.

 In connection with my exercise of the option as set forth above, I hereby represent and warrant to the Company
as follows: 
 (i)    I am purchasing the Shares for my own account for investment only, and not for
resale or with a view to the distribution thereof. 
 (ii)    I have had such an opportunity as I have
deemed adequate to obtain from the Company such information as is necessary to permit me to evaluate the merits and risks of my investment in the Company and have consulted with my own advisers with respect to my investment in the Company. 

(iii)    I have sufficient experience in business, financial and investment matters to be able to evaluate
the risks involved in the purchase of the Shares and to make an informed investment decision with respect to such purchase. 

(iv)    I can afford a complete loss of the value of the Shares and am able to bear the economic risk of
holding such Shares for an indefinite period of time. 
 (v)    I understand that the Shares may not be
registered under the Securities Act of 1933 (it being understood that the Shares are being issued and sold in reliance on the exemption provided in Rule 701 thereunder) or any applicable state securities or “blue sky” laws and may not be
sold or otherwise transferred or disposed of in the absence of an effective registration statement under the Securities Act of 1933 and under any applicable state securities or “blue sky” laws (or exemptions from the registration
requirement thereof). I further acknowledge that certificates representing Shares will bear restrictive legends reflecting the foregoing and/or that book entries for uncertificated Shares will include similar restrictive notations. 

  
 9 

 (vi)    I have read and understand the Plan and
acknowledge and agree that the Shares are subject to all of the relevant terms of the Plan, including without limitation, the transfer restrictions set forth in Section 9 of the Plan. 

(vii)    I understand and agree that the Company has a right of first refusal with respect to the Shares
pursuant to Section 9(b) of the Plan. 
 (viii)    I understand and agree that the Company has
certain repurchase rights with respect to the Shares pursuant to Section 9(c) of the Plan. 

(ix)    I understand and agree that I may not sell or otherwise transfer or dispose of the Shares for a
period of time following the effective date of a public offering by the Company as described in Section 9(f) of the Plan. 
  

			
	Sincerely yours,
	
	 
	Name:
	
	Address:
	
	 
	
	 
	
	 
		
	Date:	 	 

  
 10 

 EARLY EXERCISE 

NON-QUALIFIED STOCK OPTION GRANT NOTICE 

UNDER THE CODIAK BIOSCIENCES, INC. 

2015 STOCK OPTION AND GRANT PLAN 

Pursuant to the Codiak BioSciences, Inc. 2015 Stock Option and Grant Plan (the “Plan”), Codiak BioSciences, Inc., a Delaware
corporation (together with any successor thereto, the “Company”), has granted to the individual named below, an option (the “Stock Option”) to purchase on or prior to the Expiration Date, or such earlier date as is specified
herein, all or any part of the number of shares of Common Stock, par value $0.0001 per share (“Common Stock”), of the Company indicated below (the “Shares”), at the Option Exercise Price per share, subject to the terms and
conditions set forth in this Early Exercise Non-Qualified Stock Option Grant Notice (the “Grant Notice”), the attached Early Exercise Non-Qualified Stock
Option Agreement (the “Agreement”) and the Plan. This Stock Option is not intended to qualify as an “incentive stock option” as defined in Section 422(b) of the Internal Revenue Code of 1986, as amended from time to time
(the “Code”). 
  

	 Name of Optionee: 
	__________________ (the “Optionee”) 

  

	 No. of Shares: 
	__________ Shares of Common Stock 

  

	 Grant Date: 
	__________________ 

  

	 Vesting Commencement Date: 
	__________________ (the “Vesting Commencement Date”) 

  

	 Expiration Date: 
	__________________ (the “Expiration Date”) 

  

	 Option Exercise Price/Share: 
	$_________________ (the “Option Exercise Price”) 

  

	 Vesting Schedule: 
	 25 percent of the Shares shall vest on the first anniversary of the Vesting Commencement Date; provided that the Optionee continues to have a
Service Relationship with the Company at such time. Thereafter, the remaining 75 percent of the Shares shall vest in 36 equal monthly installments following the first anniversary of the Vesting Commencement Date, provided the Optionee continues
to have a Service Relationship with the Company on each vesting date. Notwithstanding anything in the Agreement to the contrary, in the case of a Sale Event, this Stock Option and the Shares shall be treated as provided in Section 3(c) of the
Plan[; provided, however, that if the Company is subject to a Change in Control, 50% of Optionee’s then unvested Shares shall vest immediately prior to the consummation of such Change in Control[; provided, further,
however, that if the Company is (a) subject to a Change in Control and (b) Optionee’s employment is terminated by the Company or successor corporation, as the case may be, without

  
 1 

	 	 
Cause, or Optionee terminates her employment for Good Reason, in either case, within ninety (90) days prior to the effective date of such Change in Control if the Company is in discussions
with the potential acquirer, or within twelve (12) months after the effective date of the Change in Control, then Optionee shall receive immediate acceleration of vesting of 100% of Optionee’s then unvested Shares. The terms “Change
in Control”, “Cause” and “Good Reason” have the meanings ascribed to them in the employment agreement dated [__], 201[_] by and between Optionee and the Company]. 

Attachments: Early Exercise Non-Qualified Stock Option Agreement, Restricted Stock Agreement, 2015 Stock Option
and Grant Plan 

  
 2 

 EARLY EXERCISE 

NON-QUALIFIED STOCK OPTION AGREEMENT 

UNDER THE CODIAK BIOSCIENCES, INC. 

2015 STOCK OPTION AND GRANT PLAN 

All capitalized terms used herein and not otherwise defined shall have the respective meanings set forth in the Grant Notice and the Plan.

 1.    Vesting, Exercisability and Termination. 

(a)    This Stock Option shall be immediately exercisable, regardless of whether the Shares are vested. 

(b)    Except as set forth below, and subject to the determination of the Committee in its sole discretion to accelerate
the vesting schedule hereunder, the Shares shall be vested on the respective dates indicated below: 

(i)    All Shares shall initially be unvested. 

(ii)    The Shares shall vest in accordance with the Vesting Schedule set forth in the Grant Notice. 

(c)    Termination. Except as may otherwise be provided by the Committee, if the Optionee’s Service
Relationship is terminated, the period within which to exercise this Stock Option will be subject to earlier termination as set forth below (and if not exercised within such period, shall thereafter terminate subject, in each case, to
Section 3(c) of the Plan): 
 (i)    Termination Due to Death or Disability. If the
Optionee’s Service Relationship terminates by reason of such Optionee’s death or Disability, this Stock Option may continue to be exercised, to the extent the Shares are vested on the date of termination, by the Optionee, the
Optionee’s legal representative or legatee for a period of 12 months from the date of death or Disability or until the Expiration Date, if earlier. 

(ii)    Other Termination. If the Optionee’s Service Relationship terminates for any reason
other than death or Disability, and unless otherwise determined by the Committee, this Stock Option may continue to be exercised, to the extent the Shares are vested on the date of termination, for a period of 90 days from the date of termination or
until the Expiration Date, if earlier; provided however, if the Optionee’s Service Relationship is terminated for Cause, this Stock Option shall terminate immediately upon the date of such termination. 

For purposes hereof, the Committee’s determination of the reason for termination of the Optionee’s Service Relationship shall be
conclusive and binding on the Optionee and his or her representatives or legatees and any Permitted Transferee. Any portion of this Stock Option with respect to Shares that are not vested and exercisable on the date of termination of the Service
Relationship shall terminate immediately and be null and void. 

  
 3 

 2.    Exercise of Stock Option. 

(a)    The Optionee may exercise this Stock Option only in the following manner: Prior to the Expiration Date, the Optionee
may deliver a Stock Option exercise notice (an “Exercise Notice”) in the form of Appendix A hereto indicating his or her election to purchase some or all of the Shares. Such notice shall specify the number of
Shares to be purchased. To the extent this Stock Option is only partially exercised, such exercise shall first be with respect to the Shares, if any, that have previously vested, and then with respect to the Shares that will next vest, with the
Shares that vest at the latest date being exercised last. Payment of the purchase price may be made by one or more of the methods described in Section 5 of the Plan, subject to the limitations contained in such Section of the Plan, including
the requirement that the Committee specifically approve in advance certain payment methods. 
 (b)    In the event the
Optionee exercises a portion of this Stock Option with respect to Shares that have not vested, the Optionee shall also deliver a Restricted Stock Agreement covering such unvested Shares in the form of Appendix B hereto (the “Restricted
Stock Agreement”) with the same vesting schedule for such Shares as set forth for such Shares herein. 

(c)    Notwithstanding any other provision hereof or of the Plan, no portion of this Stock Option shall be exercisable
after the Expiration Date. 
 3.    Incorporation of Plan. Notwithstanding anything herein to the contrary, this
Stock Option shall be subject to and governed by all the terms and conditions of the Plan. 
 4.    Transferability
of Stock Option. This Stock Option is personal to the Optionee and is not transferable by the Optionee in any manner other than by will or by the laws of descent and distribution. The Stock Option may be exercised during the Optionee’s
lifetime only by the Optionee (or by the Optionee’s guardian or personal representative in the event of the Optionee’s incapacity). The Optionee may elect to designate a beneficiary by providing written notice of the name of such
beneficiary to the Company, and may revoke or change such designation at any time by filing written notice of revocation or change with the Company; such beneficiary may exercise the Optionee’s Stock Option in the event of the Optionee’s
death to the extent provided herein. If the Optionee does not designate a beneficiary, or if the designated beneficiary predeceases the Optionee, the legal representative of the Optionee may exercise this Stock Option to the extent provided herein
in the event of the Optionee’s death. 
 5.    Restrictions on Transfer of Shares. The Shares acquired upon
exercise of the Stock Option shall be subject to certain transfer restrictions and other limitations including, without limitation, the provisions contained in Section 9 of the Plan and, if applicable, the Restricted Stock Agreement. 

  
 4 

 6.    Miscellaneous Provisions. 

(a)    Equitable Relief. The parties hereto agree and declare that legal remedies may be inadequate to enforce the
provisions of this Agreement and that equitable relief, including specific performance and injunctive relief, may be used to enforce the provisions of this Agreement. 

(b)    Adjustments for Changes in Capital Structure. If, as a result of any reorganization, recapitalization,
reincorporation, reclassification, stock dividend, stock split, reverse stock split or other similar change in the Common Stock, the outstanding shares of Common Stock are increased or decreased or are exchanged for a different number or kind of
securities of the Company, the restrictions contained in this Agreement shall apply with equal force to additional and/or substitute securities, if any, received by the Optionee in exchange for, or by virtue of his or her ownership of, this Stock
Option or Shares acquired pursuant thereto. 
 (c)    Change and Modifications. This Agreement may not be orally
changed, modified or terminated, nor shall any oral waiver of any of its terms be effective. This Agreement may be changed, modified or terminated only by an agreement in writing signed by the Company and the Optionee. 

(d)    Governing Law. This Agreement shall be governed by and construed in accordance with the General Corporation
Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to conflict of law principles that would
result in the application of any law other than the law of the Commonwealth of Massachusetts. 
 (e)    Headings.
The headings are intended only for convenience in finding the subject matter and do not constitute part of the text of this Agreement and shall not be considered in the interpretation of this Agreement. 

(f)    Saving Clause. If any provision(s) of this Agreement shall be determined to be illegal or unenforceable, such
determination shall in no manner affect the legality or enforceability of any other provision hereof. 

(g)    Notices. All notices, requests, consents and other communications shall be in writing and be deemed given
when delivered personally, by telex or facsimile transmission or when received if mailed by first class registered or certified mail, postage prepaid. Notices to the Company or the Optionee shall be addressed as set forth underneath their signatures
below, or to such other address or addresses as may have been furnished by such party in writing to the other. 

(h)    Benefit and Binding Effect. This Agreement shall be binding upon and shall inure to the benefit of the
parties hereto, their respective successors, assigns, and legal representatives. The Company has the right to assign this Agreement, and such assignee shall become entitled to all the rights of the Company hereunder to the extent of such assignment.

  
 5 

 (i)    Counterparts. For the convenience of the parties and to
facilitate execution, this Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which shall constitute one and the same document. 

(j)    Integration. This Agreement constitutes the entire agreement between the parties with respect to this Stock
Option and supersedes all prior agreements and discussions between the parties concerning such subject matter. 

7.    Dispute Resolution. 

(a)    Except as provided below, any dispute arising out of or relating to the Plan or this Stock Option, this Agreement,
or the breach, termination or validity of the Plan, this Stock Option or this Agreement, shall be finally settled by binding arbitration conducted expeditiously in accordance with the J.A.M.S./Endispute Comprehensive Arbitration Rules and Procedures
(the “J.A.M.S. Rules”). The arbitration shall be governed by the United States Arbitration Act, 9 U.S.C. Sections 1 - 16, and judgment upon the award rendered by the arbitrators may be entered by any court having jurisdiction thereof. The
place of arbitration shall be Massachusetts. 
 (b)    The arbitration shall commence within 60 days of the date on which
a written demand for arbitration is filed by any party hereto. In connection with the arbitration proceeding, the arbitrator shall have the power to order the production of documents by each party and any third-party witnesses. In addition, each
party may take up to three depositions as of right, and the arbitrator may in his or her discretion allow additional depositions upon good cause shown by the moving party. However, the arbitrator shall not have the power to order the answering of
interrogatories or the response to requests for admission. In connection with any arbitration, each party to the arbitration shall provide to the other, no later than seven business days before the date of the arbitration, the identity of all
persons that may testify at the arbitration and a copy of all documents that may be introduced at the arbitration or considered or used by a party’s witness or expert. The arbitrator’s decision and award shall be made and delivered within
six months of the selection of the arbitrator. The arbitrator’s decision shall set forth a reasoned basis for any award of damages or finding of liability. The arbitrator shall not have power to award damages in excess of actual compensatory
damages and shall not multiply actual damages or award punitive damages, and each party hereby irrevocably waives any claim to such damages. 

(c)    The Company, the Optionee, each party to the Agreement and any other holder of Shares issued pursuant to this
Agreement (each, a “Party”) covenants and agrees that such party will participate in the arbitration in good faith. This Section 7 applies equally to requests for temporary, preliminary or permanent injunctive relief, except that in
the case of temporary or preliminary injunctive relief any party may proceed in court without prior arbitration for the limited purpose of avoiding immediate and irreparable harm. 

(d)    Each Party (i) hereby irrevocably submits to the jurisdiction of any United States District Court of competent
jurisdiction for the purpose of enforcing the award or decision in any such proceeding, (ii) hereby waives, and agrees not to assert, by way of motion, as a defense, or otherwise, in any such suit, action or proceeding, any claim that it is not
subject personally to the jurisdiction of the above named courts, that its property is exempt or immune 

  
 6 

 
from attachment or execution (except as protected by applicable law), that the suit, action or proceeding is brought in an inconvenient forum, that the venue of the suit, action or proceeding is
improper or that this Agreement or the subject matter hereof may not be enforced in or by such court, and (iii) hereby waives and agrees not to seek any review by any court of any other jurisdiction which may be called upon to grant an
enforcement of the judgment of any such court. Each Party hereby consents to service of process by registered mail at the address to which notices are to be given. Each Party agrees that its, his or her submission to jurisdiction and its, his or her
consent to service of process by mail is made for the express benefit of each other Party. Final judgment against any Party in any such action, suit or proceeding may be enforced in other jurisdictions by suit, action or proceeding on the judgment,
or in any other manner provided by or pursuant to the laws of such other jurisdiction. 
 [SIGNATURE PAGE FOLLOWS] 

  
 7 

 The foregoing Agreement is hereby accepted and the terms and conditions thereof hereby
agreed to by the undersigned as of the date first above written. 
  

			
	CODIAK BIOSCIENCES, INC.
		
	By:	 	 
		 	Name: Doug Williams
		 	Title: President and Chief Executive Officer
	
	 Address:
  

500 Technology Square, 9th Floor

 
 Cambridge, MA 02139

 The undersigned hereby acknowledges receiving and reviewing a copy of the Plan, including, without limitation,
Section 9 thereof, and understands that this Stock Option is subject to the terms of the Plan and of this Agreement. This Agreement is hereby accepted, and the terms and conditions of the Plan, the Grant Notice and this Agreement, SPECIFICALLY
INCLUDING THE ARBITRATION PROVISIONS SET FORTH IN SECTION 7 OF THIS AGREEMENT, are hereby agreed to, by the undersigned as of the date first above written. 
  

	
	OPTIONEE:
	
	   

	Name:
	
	Address:
	
	   

	
	   

	
	   

  
 8 

 
	
	DESIGNATED BENEFICIARY:
	
	   

	
	Beneficiary’s Address:
	
	   

	
	   

	
	   

  
 9 

 Appendix A 

STOCK OPTION EXERCISE NOTICE 
 Codiak
BioSciences, Inc.  
 Attention: [____________________] 

____________________________ 
 ____________________________ 

Pursuant to the terms of the grant notice and stock option agreement between the undersigned and Codiak BioSciences, Inc. 2015 (the
“Company”) dated __________ (the “Agreement”) under the Codiak BioSciences, Inc. 2015 Stock Option and Grant Plan, I, [Insert Name] ________________, hereby [Circle One] partially/fully exercise such option
by including herein payment in the amount of $______ representing the purchase price for [Fill in number of Shares] _______ Shares. I have chosen the following form(s) of payment: 

 

							
		 	[  ]	  	1.	  	Cash
		 	[  ]	  	2.	  	Certified or bank check payable to Codiak BioSciences, Inc. 2015
		 	[  ]	  	3.	  	Other (as referenced in the Agreement and described in the Plan (please describe))
		 		  		  	______________________________________________________.

 In connection with my exercise of the option as set forth above, I hereby represent and warrant to the Company
as follows: 
 (i)    I am purchasing the Shares for my own account for investment only, and not for
resale or with a view to the distribution thereof. 
 (ii)    I have had such an opportunity as I have
deemed adequate to obtain from the Company such information as is necessary to permit me to evaluate the merits and risks of my investment in the Company and have consulted with my own advisers with respect to my investment in the Company. 

(iii)    I have sufficient experience in business, financial and investment matters to be able to evaluate
the risks involved in the purchase of the Shares and to make an informed investment decision with respect to such purchase. 

(iv)    I can afford a complete loss of the value of the Shares and am able to bear the economic risk of
holding such Shares for an indefinite period of time. 
 (v)    I understand that the Shares may not be
registered under the Securities Act of 1933 (it being understood that the Shares are being issued and sold in reliance on the exemption provided in Rule 701 thereunder) or any applicable state securities or “blue sky” laws and may not be
sold or otherwise transferred or disposed of in the absence of an effective registration statement under the Securities Act of 1933 and under any applicable state securities or “blue sky” laws (or exemptions from the registration
requirement thereof). I further acknowledge that certificates representing Shares will bear restrictive legends reflecting the foregoing and/or that book entries for uncertificated Shares will include similar restrictive notations. 

  
 10 

 (vi)    To the extent required, I have executed and
delivered to the Company the Restricted Stock Agreement attached as Appendix B to the Agreement. 

(vii)    I have read and understand the Plan and acknowledge and agree that the Shares are subject to all
of the relevant terms of the Plan, including without limitation, the transfer restrictions set forth in Section 9 of the Plan. 

(viii)    I understand and agree that the Company has a right of first refusal with respect to the Shares
pursuant to Section 9(b) of the Plan. 
 (ix)    I understand and agree that the Company has certain
repurchase rights with respect to the Shares pursuant to Section 9(c) of the Plan. 
 (x)    I
understand and agree that I may not sell or otherwise transfer or dispose of the Shares for a period of time following the effective date of a public offering by the Company as described in Section 9(f) of the Plan. 

 

			
	Sincerely yours,
	
	 
	Name:
	
	Address:
	
	 
	
	 
	
	 
		
	Date:	 	 

  
 11 

 Appendix B 

RESTRICTED STOCK AGREEMENT FOR EARLY EXERCISE OPTION 

UNDER THE CODIAK BIOSCIENCES, INC. 

2015 STOCK OPTION AND GRANT PLAN 

All capitalized terms used herein and not otherwise defined shall have the respective meanings set forth in the Early Exercise Non-Qualified Stock Option Grant Notice (the “Grant Notice”) and Early Exercise Non-Qualified Stock Option Agreement (the “Option Agreement”)
between Codiak BioSciences, Inc. (the “Company”) and _______________ (the “Grantee”) for __________________ Shares of Common Stock with a Grant Date of ___________, ______ under the Codiak BioSciences, Inc. 2015
Stock Option and Grant Plan (the “Plan”). 
 1.    Purchase and Sale of Shares; Vesting. 

(a)    Purchase and Sale. The Company hereby sells to the Grantee, and the Grantee hereby purchases from the
Company, on ________________, 20[__],the number of Shares set forth in the Stock Option Exercise Notice (_______ Shares) dated __________ , pursuant to the Grant Notice and Option Agreement, for the aggregate Option Exercise Price for the Shares so
purchased. 
 (b)    Vesting. The risk of forfeiture shall lapse with respect to the Shares, and such Shares shall
become vested, on the respective dates indicated on the Vesting Schedule set forth in the Grant Notice. 

2.    Repurchase Right. Upon a Termination Event, the Company shall have the right to repurchase Shares of
Restricted Stock that are unvested as of the date of such Termination Event as set forth in Section 9(c) of the Plan. 

3.    Restrictions on Transfer of Shares. The Shares (whether or not vested) shall be subject to certain transfer
restrictions and other limitations including, without limitation, the provisions contained in Section 9 of the Plan 

4.    Incorporation of Plan. Notwithstanding anything herein to the contrary, this Restricted Stock Agreement shall
be subject to and governed by all the terms and conditions of the Plan. 
 5.    Miscellaneous Provisions. 

(a)    Record Owner; Dividends. The Grantee and any Permitted Transferees, during the duration of this Agreement,
shall be considered the record owners of and shall be entitled to vote the Shares if and to the extent the Shares are entitled to voting rights. The Grantee and any Permitted Transferees shall be entitled to receive all dividends and any other
distributions declared on the Shares; provided, however, that the Company is under no duty to declare any such dividends or to make any such distribution. 

 (b)    Section 83(b) Election. The Grantee shall consult with the
Grantee’s tax advisor to determine whether it would be appropriate for the Grantee to make an election under Section 83(b) of the Code with respect to the Shares. Any such election must be filed with the Internal Revenue Service within 30
days of the date of exercise. If the Grantee makes an election under Section 83(b) of the Code, the Grantee shall give prompt notice to the Company (and provide a copy of such election to the Company). 

(c)    Equitable Relief. The parties hereto agree and declare that legal remedies may be inadequate to enforce the
provisions of this Agreement and that equitable relief, including specific performance and injunctive relief, may be used to enforce the provisions of this Agreement. 

(d)    Change and Modifications. This Agreement may not be orally changed, modified or terminated, nor shall any
oral waiver of any of its terms be effective. This Agreement may be changed, modified or terminated only by an agreement in writing signed by the Company and the Grantee. 

(e)    Governing Law. This Agreement shall be governed by and construed in accordance with the General Corporation
Law of the State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of Massachusetts, without regard to conflict of law principles that would result
in the application of any law other than the law of the Commonwealth of Massachusetts. 
 (f)    Headings. The
headings are intended only for convenience in finding the subject matter and do not constitute part of the text of this Agreement and shall not be considered in the interpretation of this Agreement. 

(g)    Saving Clause. If any provision(s) of this Agreement shall be determined to be illegal or unenforceable, such
determination shall in no manner affect the legality or enforceability of any other provision hereof. 

(h)    Notices. All notices, requests, consents and other communications shall be in writing and be deemed given
when delivered personally, by telex or facsimile transmission or when received if mailed by first class registered or certified mail, postage prepaid. Notices to the Company or the Grantee shall be addressed as set forth underneath their signatures
below, or to such other address or addresses as may have been furnished by such party in writing to the other. 

(i)    Benefit and Binding Effect. This Agreement shall be binding upon and shall inure to the benefit of the
parties hereto, their respective successors, assigns, and legal representatives. The Company has the right to assign this Agreement, and such assignee shall become entitled to all the rights of the Company hereunder to the extent of such assignment.

 (j)    Counterparts. For the convenience of the parties and to facilitate execution, this Agreement may be
executed in two or more counterparts, each of which shall be deemed an original, but all of which shall constitute one and the same document. 

  
 13 

 6.    Dispute Resolution. 

(a)    Except as provided below, any dispute arising out of or relating to the Plan or the Shares, this Agreement, or the
breach, termination or validity of the Plan, the Shares or this Agreement, shall be finally settled by binding arbitration conducted expeditiously in accordance with the J.A.M.S./Endispute Comprehensive Arbitration Rules and Procedures (the
“J.A.M.S. Rules”). The arbitration shall be governed by the United States Arbitration Act, 9 U.S.C. Sections 1 - 16, and judgment upon the award rendered by the arbitrators may be entered by any court having jurisdiction thereof. The place
of arbitration shall be Commonwealth of Massachusetts. 
 (b)    The arbitration shall commence within 60 days of the
date on which a written demand for arbitration is filed by any party hereto. In connection with the arbitration proceeding, the arbitrator shall have the power to order the production of documents by each party and any third-party witnesses. In
addition, each party may take up to three depositions as of right, and the arbitrator may in his or her discretion allow additional depositions upon good cause shown by the moving party. However, the arbitrator shall not have the power to order the
answering of interrogatories or the response to requests for admission. In connection with any arbitration, each party to the arbitration shall provide to the other, no later than seven business days before the date of the arbitration, the identity
of all persons that may testify at the arbitration and a copy of all documents that may be introduced at the arbitration or considered or used by a party’s witness or expert. The arbitrator’s decision and award shall be made and delivered
within six months of the selection of the arbitrator. The arbitrator’s decision shall set forth a reasoned basis for any award of damages or finding of liability. The arbitrator shall not have power to award damages in excess of actual
compensatory damages and shall not multiply actual damages or award punitive damages, and each party hereby irrevocably waives any claim to such damages. 

(c)    The Company, the Grantee, each party to the Agreement and any other holder of Shares issued pursuant to this
Agreement (each, a “Party”) covenants and agrees that such party will participate in the arbitration in good faith. This Section 6 applies equally to requests for temporary, preliminary or permanent injunctive relief, except that in
the case of temporary or preliminary injunctive relief any party may proceed in court without prior arbitration for the limited purpose of avoiding immediate and irreparable harm. 

(d)    Each Party (i) hereby irrevocably submits to the jurisdiction of any United States District Court of competent
jurisdiction for the purpose of enforcing the award or decision in any such proceeding, (ii) hereby waives, and agrees not to assert, by way of motion, as a defense, or otherwise, in any such suit, action or proceeding, any claim that it is not
subject personally to the jurisdiction of the above named courts, that its property is exempt or immune from attachment or execution (except as protected by applicable law), that the suit, action or proceeding is brought in an inconvenient forum,
that the venue of the suit, action or proceeding is improper or that this Agreement or the subject matter hereof may not be enforced in or by such court, and (iii) hereby waives and agrees not to seek any review by any court of any other
jurisdiction which may be called upon to grant an enforcement of the judgment of any such court. Each Party hereby consents to service of process by registered mail at the address to which notices are to be given. Each Party agrees that its, his or
her submission to jurisdiction 

  
 14 

 
and its, his or her consent to service of process by mail is made for the express benefit of each other Party. Final judgment against any Party in any such action, suit or proceeding may be
enforced in other jurisdictions by suit, action or proceeding on the judgment, or in any other manner provided by or pursuant to the laws of such other jurisdiction. 

[SIGNATURE PAGE FOLLOWS] 

  
 15 

 The foregoing Restricted Stock Agreement is hereby accepted and the terms and conditions
thereof are hereby agreed to by the undersigned as of the date written in Section 1(a) above. 
  

			
	CODIAK BIOSCIENCES, INC.
		
	By:	 	 
		 	Name:
		 	Title:
	
	Address:
	
	 
	
	 
	
	 

 The undersigned hereby acknowledges receiving and reviewing a copy of the Plan, including, without limitation,
Section 9 thereof and understands that the Shares purchased hereby are subject to the terms of the Plan, the Grant Notice, and this Agreement. This Agreement is hereby accepted, and the terms and conditions of the Plan, the Grant Notice and
this Agreement, SPECIFICALLY INCLUDING THE ARBITRATION PROVISIONS SET FORTH IN SECTION 6 OF THIS AGREEMENT, are hereby agreed to, by the undersigned as of the date first above written. 

 

	
	GRANTEE:
	
	   

	Name:
	
	Address:EX-10.2

 Exhibit 10.2 

CODIAK BIOSCIENCES, INC. 

2020 STOCK OPTION AND INCENTIVE PLAN 

SECTION 1. GENERAL PURPOSE OF THE PLAN; DEFINITIONS 

The Plan’s purpose is to enhance the Company’s ability to attract, retain and motivate persons who make (or are expected to make)
important contributions to the Company by providing these individuals with equity ownership opportunities. 
 SECTION 2. ADMINISTRATION OF PLAN;
ADMINISTRATOR AUTHORITY TO SELECT PARTICIPANTS AND DETERMINE AWARDS 
 (a)    Administration of Plan. The Plan
shall be administered by the Administrator. 
 (b)    Powers of Administrator. The Administrator shall have the
power and authority to grant Awards consistent with the terms of the Plan, including the power and authority: 

(i)    to select the individuals to whom Awards may be granted; 

(ii)    to determine the time or times of grant, and the extent, and any combination of Incentive Stock Options, Non-Qualified Stock Options, Stock Appreciation Rights, Restricted Stock Awards, Restricted Stock Units, Unrestricted Stock Awards, Cash-Based Awards, and Dividend Equivalent Rights; 

(iii)    to determine the number of shares of Stock to be covered by any Award; 

(iv)    to determine and modify the terms and conditions, including restrictions, of any Award, which terms and conditions
may differ among individual Awards and Participants, and to approve the forms of Award Agreements; 
 (v)    to
accelerate at any time the exercisability or vesting of all or any portion of any Award; 
 (vi)    subject to the
provisions of Section 5(c), to extend at any time the period in which Stock Options may be exercised; 

(vii)    to take all actions and make all determinations under the Plan; to interpret the Plan and Award Agreements, to
adopt and amend and repeal Plan administrative rules, guidelines and practices as it deems advisable; and 

(viii)    to correct defects and ambiguities, supply omissions and reconcile inconsistencies in the Plan or any Award as
it deems necessary or appropriate to administer the Plan and any Awards. 
 The Administrator’s determinations under the Plan are in its sole
discretion and will be final and binding on all persons having or claiming any interest in the Plan or any Award. 

 (c)    Delegation of Authority to Grant Awards. Subject to
applicable law, the Administrator, in its discretion, may delegate to a committee consisting of one or more officers of the Company including the Chief Executive Officer of the Company all or part of the Administrator’s authority and duties
with respect to the granting of Awards to individuals who are (i) not subject to the reporting and other provisions of Section 16 of the Exchange Act and (ii) not members of the delegated committee. The Administrator may revoke or
amend the terms of a delegation at any time but such action shall not invalidate any prior actions of the Administrator’s delegate or delegates that were consistent with the terms of the Plan. 

(d)    Award Agreement. Awards under the Plan shall be evidenced by Award Agreements that describe the terms,
conditions and limitations for each Award which may include, without limitation, the term of an Award and the provisions applicable in the event employment or service terminates. 

(e)    Indemnification. Notwithstanding any other provisions of the Plan, no individual acting as director,
officer, other employee or agent of the Company or any Subsidiary will be liable to any Participant, former Participant, spouse, beneficiary, or any other person for any claim, loss, liability, or expense incurred in connection with the Plan or any
Award, and such individual will not be personally liable with respect to the Plan because of any contract or other instrument executed in his or her capacity as an Administrator, director, officer or other agent of the Company or any Subsidiary. The
Company will indemnify and hold harmless each director, officer, or other agent of the Company or any Subsidiary that has been or will be granted or delegated any duty or power relating to the Plan’s administration or interpretation, against
any cost or expense (including attorney’s fees) or liability (including any sum paid in settlement of a claim with the Administrator’s approval) arising from any act or omission concerning this Plan, unless arising from such person’s
own fraud or bad faith. 
 (f)    Provisions for Foreign Award Participants. The Administrator may modify Awards
granted to Participants who are foreign nationals or employed outside of the United States or establish subplans or procedures under the Plan to address differences in laws, rules, regulations or customs of such foreign jurisdictions with respect to
tax, securities, currency, employee benefit or other matters. Notwithstanding the foregoing, the Administrator may not take any actions hereunder, and no Awards shall be granted, that would violate the Exchange Act or any other applicable United
States securities law, the Code, or any other applicable United States governing statute or law. 
 SECTION 3. STOCK ISSUABLE UNDER THE PLAN; MERGERS;
SUBSTITUTION 
 (a)    Number of Shares. Subject to adjustment under Sections 3(e) and 3(f) and the terms of
this Section 3, Awards may be made under the Plan covering up to the Overall Share Limit. As of the Plan’s Effective Date, the Company will cease granting awards under the Prior Plan; however, Prior Plan awards will remain subject to the
terms of the Prior Plan. Shares issued under the Plan may consist of authorized but unissued Stock, Stock purchased on the open market or treasury Stock. 

(b)    The maximum aggregate number of shares of Stock that may be issued in the form of Incentive Stock Options shall not
exceed 10,000,000 shares of Stock. 

  
 2 

 (c)    Share Recycling. The shares of Stock underlying any awards
under the Plan and under the Company’s 2015 Stock Option and Grant Plan that are forfeited, canceled, held back upon exercise of an Option or settlement of an Award to cover the exercise price or tax withholding, reacquired by the Company prior
to vesting, satisfied without the issuance of Stock or otherwise terminated (other than by exercise) shall be added back to the shares of Stock available for issuance under the Plan. In the event the Company repurchases shares of Stock on the open
market, such shares shall not be added to the shares of Stock available for issuance under the Plan. To the extent an Award under the Plan is paid out in cash rather than shares of Stock, such cash payment will not result in reducing the number of
shares of Stock available for issuance under the Plan. 
 (d)    Maximum Awards to
Non-Employee Directors. Notwithstanding anything to the contrary in this Plan, the value of all Awards awarded under this Plan and all other cash compensation paid by the Company to any Non-Employee Director in any calendar year shall not exceed $500,000 or $750,000 during the first year of appointment. For the purpose of this limitation, the value of any Award shall be its grant date fair value,
as determined in accordance with ASC 718 or successor provision but excluding the impact of estimated forfeitures related to service-based vesting provisions. 

(e)    Equity Restructuring. In connection with any Equity Restructuring, subject to Section 3(f), the
Administrator will equitably adjust the maximum number of shares reserved for issuance under the Plan, including the maximum number of shares that may be issued as Incentive Stock Options, and each outstanding Award as it deems appropriate to
reflect the Equity Restructuring, which may include adjusting the number and type of securities subject to each outstanding Award and/or the Award’s exercise price or grant price (if applicable), granting new Awards to Participants, and making
a cash payment to Participants. The adjustments provided under this Section 3(e) will be non-discretionary and final and binding on the affected Participants and the Company; provided that the
Administrator will determine whether an adjustment is equitable. 
 (f)    Sale Events. In the case of a consummated Sale Event, the Administrator shall have the option (in its sole discretion) to take any of the following actions (without the consent of a Participant) to facilitate such
transaction: 
 (i)    approve or otherwise cause the assumption or continuation of Awards, or the substitution of such
Awards with new Awards of the successor entity or parent thereof, with appropriate adjustment as to the number and kind of shares; 

(ii)    make or provide for a payment, in cash or in kind, to the Participants holding Options and Stock Appreciation
Rights, in exchange for the cancellation thereof, an amount equal to the difference between (A) the Sale Price multiplied by the number of shares of Stock subject to outstanding Options and Stock Appreciation Rights (to the extent then vested,
after giving effect to any discretionary acceleration under Section 2(b)(v), any acceleration herein and any acceleration contained in an Award Agreement, at prices not in excess of the Sale Price) and (B) the aggregate exercise price of
all such outstanding Options and Stock Appreciation Rights (provided that, in the case of an Option or Stock Appreciation Right with an exercise price equal to or greater than the Sale Price, such Option or Stock Appreciation Right shall be
cancelled for no consideration); 

  
 3 

 (iii)    permit each Participant, within a specified period of time
prior to the consummation of the Sale Event as determined by the Administrator, to exercise all outstanding Options and Stock Appreciation Rights (to the extent then exercisable, after giving effect to any discretionary acceleration under
Section 2(b)(v), any acceleration herein and any acceleration contained in an Award Agreement) held by such Participant after which all unexercised Options and Stock Appreciation Rights shall terminate; 

(iv)    make or provide for a payment, in cash or in kind, to the Participants holding Awards other than Options and Stock
Appreciation Rights, in exchange for the cancellation thereof, an amount equal to the Sale Price multiplied by the number of vested shares of Stock underlying such Awards (after giving effect to any discretionary acceleration under
Section 2(b)(v), any acceleration herein and any acceleration contained in an Award Agreement); or 
 (v)    any
combination of the foregoing. 
 Notwithstanding anything to the contrary in this Plan, to the extent that Awards are not assumed,
substituted or continued by the Company or its successor in a Sale Event, all Options and Stock Appreciation Rights with time-based vesting conditions or restrictions that are not vested and/or exercisable immediately prior to the effective time of
the Sale Event shall become fully vested and exercisable as of the effective time of the Sale Event, all other Awards with time-based vesting, conditions or restrictions shall become fully vested and nonforfeitable as of the effective time of the
Sale Event, and all Awards with conditions and restrictions relating to the attainment of performance goals may become vested and nonforfeitable in connection with a Sale Event in the Administrator’s discretion or to the extent specified in the
relevant Award Agreement. 
 SECTION 4. ELIGIBILITY 

Participants under the Plan will be such employees, Non-Employee Directors and Consultants of the
Company and its Affiliates as are selected from time to time by the Administrator in its sole discretion. 
 SECTION 5. STOCK OPTIONS 

(a)    Award of Stock Options. The Administrator may grant Stock Options under the Plan. Any Stock Option granted
under the Plan shall be in such form as approved by the Administrator. 
 Stock Options granted under the Plan may be either Incentive Stock
Options or Non-Qualified Stock Options. Incentive Stock Options may be granted only to employees of the Company or any Subsidiary that is a “subsidiary corporation” within the meaning of
Section 424(f) of the Code. To the extent that any Option does not qualify as an Incentive Stock Option, it shall be deemed a Non-Qualified Stock Option. 

  
 4 

 If the Administrator so determines, Stock Options may be granted in lieu of cash
compensation at the Participant’s election, subject to such terms and conditions as the Administrator may establish. Stock Options granted pursuant to this Section 5 shall be subject to the following terms and conditions. 

(b)    Exercise Price. The Administrator will establish each Option’s exercise price and specify the exercise
price in the Award Agreement. The exercise price will not be less than 100% of the fair market value on the grant date of the Option. In the case of an Incentive Stock Option that is granted to a Ten Percent Owner, the exercise price of such
Incentive Stock Option shall be not less than 110 percent of the Fair Market Value on the grant date. Notwithstanding the foregoing, Stock Options may be granted with an exercise price per share that is less than 100 percent of the Fair
Market Value on the date of grant pursuant to a transaction described in, and in a manner consistent with, Section 424(a) of the Code. 

(c)    Option Term. The term of each Stock Option shall be fixed by the Administrator, but no Stock Option shall be
exercisable more than ten years after the date the Stock Option is granted. In the case of an Incentive Stock Option that is granted to a Ten Percent Owner, the term of such Stock Option shall be no more than five years from the date of grant. 

(d)    Exercisability; Rights of a Stockholder. Stock Options shall become exercisable at such time or times,
whether or not in installments, as shall be determined by the Administrator at or after the grant date. The Administrator may at any time accelerate the exercisability of all or any portion of any Stock Option. A Participant shall have the rights of
a stockholder only as to shares acquired upon the exercise of a Stock Option and not as to unexercised Stock Options. 

(e)    Method of Exercise. Stock Options may be exercised in whole or in part, by giving written or electronic
notice of exercise to the Company, specifying the number of shares to be purchased. Payment of the purchase price may be made by one or more of the following methods except to the extent otherwise provided in the Option Award Agreement: 

(i)    in cash, by certified or bank check or other instrument acceptable to the Administrator; 

(ii)    through the delivery (or attestation to the ownership following such procedures as the Company may prescribe) of
shares of Stock that are not then subject to restrictions under any Company plan. Such surrendered shares shall be valued at Fair Market Value on the exercise date; 

(iii)    by the Participant delivering to the Company a properly executed exercise notice together with irrevocable
instructions to a broker to promptly deliver to the Company cash or a check payable and acceptable to the Company for the purchase price; provided that in the event the Participant chooses to pay the purchase price as so provided, the Participant
and the broker shall comply with such procedures and enter into such agreements of indemnity and other agreements as the Company shall prescribe as a condition of such payment procedure; or 

(iv)    with respect to Stock Options that are not Incentive Stock Options, by a “net exercise” arrangement
pursuant to which the Company will reduce the number of shares of Stock issuable upon exercise by the largest whole number of shares with a Fair Market Value that does not exceed the aggregate exercise price. 

  
 5 

 Payment instruments will be received subject to collection. The transfer to the Participant
on the records of the Company or of the transfer agent of the shares of Stock to be purchased pursuant to the exercise of a Stock Option will be contingent upon receipt from the Participant (or a purchaser acting in his stead in accordance with the
provisions of the Stock Option) by the Company of the full purchase price for such shares and the fulfillment of any other requirements contained in the Option Award Agreement or applicable provisions of laws (including the satisfaction of any
withholding taxes that the Company is obligated to withhold with respect to the Participant). In the event a Participant chooses to pay the purchase price by previously-owned shares of Stock through the attestation method, the number of shares of
Stock transferred to the Participant upon the exercise of the Stock Option shall be net of the number of attested shares. In the event that the Company establishes, for itself or using the services of a third party, an automated system for the
exercise of Stock Options, such as a system using an internet website or interactive voice response, then the paperless exercise of Stock Options may be permitted through the use of such an automated system. 

(f)    Annual Limit on Incentive Stock Options. To the extent required for “incentive stock option”
treatment under Section 422 of the Code, the aggregate Fair Market Value (determined as of the time of grant) of the shares of Stock with respect to which Incentive Stock Options granted under this Plan and any other plan of the Company or its
parent and subsidiary corporations become exercisable for the first time by an Participant during any calendar year shall not exceed $100,000. To the extent that any Stock Option exceeds this limit, it shall constitute a Non-Qualified Stock Option. 
 SECTION 6. STOCK APPRECIATION RIGHTS 

(a)    Award of Stock Appreciation Rights. The Administrator may grant Stock Appreciation Rights under the Plan.

 (b)    Exercise Price of Stock Appreciation Rights. The exercise price of a Stock Appreciation Right shall not
be less than 100 percent of the Fair Market Value of the Stock on the date of grant. 
 (c)    Grant and
Exercise of Stock Appreciation Rights. Stock Appreciation Rights may be granted by the Administrator independently of any Stock Option granted pursuant to Section 5 of the Plan. 

(d)    Terms and Conditions of Stock Appreciation Rights. Stock Appreciation Rights shall be subject to terms and
conditions as determined on the date of grant by the Administrator and may differ among individual Awards and Participants. The term of a Stock Appreciation Right may not exceed ten years. 

SECTION 7. RESTRICTED STOCK AWARDS 

(a)    Nature of Restricted Stock Awards. The Administrator may grant Restricted Stock Awards under the Plan. 

  
 6 

 (b)    Rights as a Stockholder. Upon the grant of the Restricted
Stock Award and payment of any applicable purchase price, a Participant shall have the rights of a stockholder with respect to the voting of the Restricted Shares and receipt of dividends; provided that if the lapse of restrictions with respect to
the Restricted Stock Award is tied to the attainment of performance goals, any dividends paid by the Company during the performance period shall accrue and shall not be paid to the Participant until and to the extent the performance goals are met.
Unless the Administrator otherwise determines, uncertificated Restricted Shares shall be accompanied by a notation on the records of the Company or the transfer agent to the effect that they are subject to forfeiture until such Restricted Shares are
vested as provided in Section 7(d) below, and the Participant shall be required, as a condition of the grant, to deliver to the Company such instruments of transfer as the Administrator may prescribe. 

(c)    Restrictions. Restricted Shares may not be sold, assigned, transferred, pledged or otherwise encumbered or
disposed of except as specifically provided herein or in the Restricted Stock Award Agreement. If a Participant’s employment (or other Service Relationship) with the Company and its Subsidiaries terminates for any reason, any Restricted Shares
that have not vested at the time of termination shall automatically and without any action on behalf of the Company, be deemed to have been reacquired by the Company at its original purchase price (if any) from such Participant or such
Participant’s legal representative simultaneously with such termination of employment (or other Service Relationship), and thereafter shall cease to represent any ownership of the Company by the Participant or rights of the Participant as a
stockholder. Following such deemed reacquisition of Restricted Shares that are represented by physical certificates, a Participant shall surrender such certificates to the Company upon request without consideration. 

(d)    Vesting of Restricted Shares. The Administrator at the time of grant shall specify the date or dates and/or
the attainment of pre-established performance goals, objectives and other conditions on which the non-transferability of the Restricted Shares and the Company’s
right of repurchase or forfeiture shall lapse. Subsequent to such date or dates and/or the attainment of such pre-established performance goals, objectives and other conditions, the shares on which all
restrictions have lapsed shall no longer be Restricted Shares and shall be deemed “vested.” 
 SECTION 8. RESTRICTED STOCK UNITS 

(a)    Nature of Restricted Stock Units. The Administrator may grant Restricted Stock Units under the Plan. A
Restricted Stock Unit is an Award of stock units that may be settled in shares of Stock (or cash, to the extent explicitly provided for in the Award Agreement) upon the satisfaction of such restrictions and conditions at the time of grant.
Conditions may be based on continuing employment (or other Service Relationship) and/or achievement of pre-established performance goals and objectives. The terms and conditions of each such Award shall be
determined by the Administrator, and such terms and conditions may differ among individual Awards and Participants. Except in the case of Restricted Stock Units with a deferred settlement date that complies with Section 409A, at the end of the
vesting period, the Restricted Stock Units, to the extent vested, shall be settled in the form of shares of Stock or cash if explicitly provided for in the Award Agreement. Restricted Stock Units with deferred settlement dates are subject to
Section 409A and shall contain such additional terms and conditions as the Administrator shall determine in its sole discretion in order to comply with the requirements of Section 409A. 

  
 7 

 (b)    Election to Receive Restricted Stock Units in Lieu of
Compensation. The Administrator may permit a Participant to elect to receive a portion of future cash compensation otherwise due to such Participant in the form of an award of Restricted Stock Units. Any such election shall be made in writing
and shall be delivered to the Company no later than the date specified by the Administrator and in accordance with Section 409A and such other rules and procedures established by the Administrator. Any such future cash compensation that the
Participant elects to defer shall be converted to a fixed number of Restricted Stock Units based on the Fair Market Value of Stock on the date the compensation would otherwise have been paid to the Participant if such payment had not been deferred
as provided herein. The Administrator shall have the sole right to determine whether and under what circumstances to permit such elections and to impose such limitations and other terms and conditions thereon as the Administrator deems appropriate.
Any Restricted Stock Units that are elected to be received in lieu of cash compensation shall be fully vested, unless otherwise provided in the Award Agreement. 

(c)    Rights as a Stockholder. A Participant shall have the rights as a stockholder only as to shares of Stock
acquired by the Participant upon settlement of Restricted Stock Units; provided, however, that the Participant may be credited with Dividend Equivalent Rights with respect to the stock units underlying his Restricted Stock Units, subject to the
provisions of Section 11 and such terms and conditions as the Administrator may determine. 

(d)    Termination. Except as may otherwise be provided by the Administrator either in the Award Agreement or,
subject to Section 16 below, in writing after the Award is issued, a Participant’s right in all Restricted Stock Units that have not vested shall automatically terminate upon the Participant’s termination of employment (or cessation
of Service Relationship) with the Company and its Subsidiaries for any reason. 
 SECTION 9. UNRESTRICTED STOCK AWARDS 

Grant or Sale of Unrestricted Stock. The Administrator may grant (or sell at par value or such higher purchase price determined by the
Administrator) an Unrestricted Stock Award under the Plan. An Unrestricted Stock Award is an Award pursuant to which the Participant may receive shares of Stock free of any restrictions under the Plan. Unrestricted Stock Awards may be granted in
respect of past services or other valid consideration, or in lieu of cash compensation due to such Participant. 
 SECTION 10. CASH-BASED AWARDS 

Grant of Cash-Based Awards. The Administrator may grant Cash-Based Awards under the Plan. A Cash-Based Award is an Award that entitles
the Participant to a payment in cash upon the attainment of specified performance goals. The Administrator shall determine the maximum duration of the Cash-Based Award, the amount of cash to which the Cash-Based Award pertains, the conditions upon
which the Cash-Based Award shall become vested or payable, and such other provisions as the Administrator shall determine. Each Cash-Based 

  
 8 

 
Award shall specify a cash-denominated payment amount, formula or payment ranges as determined by the Administrator. Payment, if any, with respect to a Cash-Based Award shall be made in
accordance with the terms of the Award and may be made in cash. 
 SECTION 11. DIVIDEND EQUIVALENT RIGHTS 

(a)    Dividend Equivalent Rights. The Administrator may grant Dividend Equivalent Rights under the Plan. A Dividend
Equivalent Right is an Award entitling the Participant to receive credits based on cash dividends that would have been paid on the shares of Stock specified in the Dividend Equivalent Right (or other Award to which it relates) if such shares had
been issued to the Participant. A Dividend Equivalent Right may be granted hereunder to any Participant as a component of an award of Restricted Stock Units or as a freestanding Award. The terms and conditions of Dividend Equivalent Rights shall be
specified in the Award Agreement. Dividend equivalents credited to the holder of a Dividend Equivalent Right may be paid currently or may be deemed to be reinvested in additional shares of Stock, which may thereafter accrue additional equivalents.
Any such reinvestment shall be at Fair Market Value on the date of reinvestment or such other price as may then apply under a dividend reinvestment plan sponsored by the Company, if any. Dividend Equivalent Rights may be settled in cash or shares of
Stock or a combination thereof, in a single installment or installments. A Dividend Equivalent Right granted as a component of an Award of Restricted Stock Units shall provide that such Dividend Equivalent Right shall be settled only upon settlement
or payment of, or lapse of restrictions on, such other Award, and that such Dividend Equivalent Right shall expire or be forfeited or annulled under the same conditions as such other Award. 

(b)    Termination. Except as may otherwise be provided by the Administrator either in the Award Agreement or,
subject to Section 16 below, in writing after the Award is issued, a Participant’s rights in all Dividend Equivalent Rights shall automatically terminate upon the Participant’s termination of employment (or cessation of Service
Relationship) with the Company and its Subsidiaries for any reason. 
 SECTION 12. TRANSFERABILITY OF AWARDS 

(a)    Transferability. Except as provided in Section 12(b) below, during a Participant’s lifetime, his or
her Awards shall be exercisable only by the Participant, or by the Participant’s legal representative or guardian in the event of the Participant’s incapacity. No Awards shall be sold, assigned, transferred or otherwise encumbered or
disposed of by a Participant other than by will or by the laws of descent and distribution or pursuant to a domestic relations order. No Awards shall be subject, in whole or in part, to attachment, execution, or levy of any kind, and any purported
transfer in violation hereof shall be null and void. 
 (b)    Administrator Action. Notwithstanding
Section 12(a), the Administrator, in its discretion, may provide either in the Award Agreement regarding a given Award or by subsequent written approval that the Participant (who is an employee or director) may transfer his or her Non-Qualified Stock Options to his or her immediate family members, to trusts for the benefit of such family members, or to partnerships in which such family members are the only partners, provided that the
transferee agrees in writing with the Company to be bound by all of the terms and conditions of this Plan and the applicable Award. In no event may an Award be transferred by a Participant for value. 

  
 9 

 (c)    Family Member. For purposes of Section 12(b),
“family member” shall mean a Participant’s child, stepchild, grandchild, parent, stepparent, grandparent, spouse, former spouse, sibling, niece, nephew,
mother-in-law, father-in-law, son-in-law, daughter-in-law, brother-in-law, or sister-in-law, including adoptive relationships, any person sharing the Participant’s household (other than a tenant of the Participant), a trust in which these persons
(or the Participant) have more than 50 percent of the beneficial interest, a foundation in which these persons (or the Participant) control the management of assets, and any other entity in which these persons (or the Participant) own more than
50 percent of the voting interests. 
 (d)    Designation of Beneficiary. To the extent permitted by the
Company, each Participant to whom an Award has been made under the Plan may designate a beneficiary or beneficiaries to exercise any Award or receive any payment under any Award payable on or after the Participant’s death. Any such designation
shall be on a form provided for that purpose by the Administrator and shall not be effective until received by the Administrator. If no beneficiary has been designated by a deceased Participant, or if the designated beneficiaries have predeceased
the Participant, the beneficiary shall be the Participant’s estate. 
 SECTION 13. TAX WITHHOLDING 

(a)    Payment by Participant. Each Participant shall, no later than the date as of which the value of an Award or
of any Stock or other amounts received thereunder first becomes includable in the gross income of the Participant for income tax purposes, pay to the Company, or make arrangements satisfactory to the Administrator regarding payment of, any Federal,
state, or local taxes of any kind required by law to be withheld by the Company with respect to such income. The Company and its Subsidiaries shall, to the extent permitted by law, have the right to deduct any such taxes from any payment of any kind
otherwise due to the Participant. The Company’s obligation to deliver evidence of book entry (or stock certificates) to any Participant is subject to and conditioned on tax withholding obligations being satisfied by the Participant. 

(b)    Payment in Stock. The Administrator may require the Company’s tax withholding obligation to be
satisfied, in whole or in part, by the Company withholding from shares of Stock to be issued pursuant to any Award a number of shares with an aggregate Fair Market Value (as of the date the withholding is effected) that would satisfy the withholding
amount due; provided, however, that the amount withheld does not exceed the maximum statutory tax rate or such lesser amount as is necessary to avoid liability accounting treatment. For purposes of share withholding, the Fair Market Value of
withheld shares shall be determined in the same manner as the value of Stock includible in income of the Participants. The Administrator may also require the Company’s tax withholding obligation to be satisfied, in whole or in part, by an
arrangement whereby a certain number of shares of Stock issued pursuant to any Award are immediately sold and proceeds from such sale are remitted to the Company in an amount that would satisfy the withholding amount due. 

  
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 SECTION 14. SECTION 409A AWARDS 

Awards are intended to be exempt from Section 409A to the greatest extent possible and to otherwise comply with Section 409A. The
Plan and all Awards shall be interpreted in accordance with such intent. To the extent that any Award is determined to constitute “nonqualified deferred compensation” within the meaning of Section 409A (a “409A Award”), the
Award shall be subject to such additional rules and requirements as specified by the Administrator from time to time in order to comply with Section 409A. In this regard, if any amount under a 409A Award is payable upon a “separation from
service” (within the meaning of Section 409A) to a Participant who is then considered a “specified employee” (within the meaning of Section 409A), then no such payment shall be made prior to the date that is the earlier of
(i) six months and one day after the Participant’s separation from service, or (ii) the Participant’s death, but only to the extent such delay is necessary to prevent such payment from being subject to interest, penalties and/or
additional tax imposed pursuant to Section 409A. Further, the settlement of any 409A Award may not be accelerated except to the extent permitted by Section 409A. 

SECTION 15. TERMINATION OF SERVICE RELATIONSHIP, TRANSFER, LEAVE OF ABSENCE, ETC. 

(a)    Termination of Service Relationship. If the Participant’s Service Relationship is with an Affiliate and
such Affiliate ceases to be an Affiliate, the Participant shall be deemed to have terminated his or her Service Relationship for purposes of the Plan. 

(b)    For purposes of the Plan, the following events shall not be deemed a termination of a Service Relationship: 

(i)    a transfer to the employment of the Company from an Affiliate or from the Company to an Affiliate, or from one
Affiliate to another; or 
 (ii)    an approved leave of absence for military service or sickness, or for any other
purpose approved by the Company, if the employee’s right to re-employment is guaranteed either by a statute or by contract or under the policy pursuant to which the leave of absence was granted or if the
Administrator otherwise so provides in writing. 
 SECTION 16. AMENDMENTS AND TERMINATION 

The Board may, at any time, amend or discontinue the Plan and the Administrator may, at any time, amend or cancel any outstanding Award for the
purpose of satisfying changes in law or for any other lawful purpose, but no such action shall materially and adversely affect rights under any outstanding Award without the holder’s consent. The Administrator is specifically authorized to
exercise its discretion to reduce the exercise price of outstanding Stock Options or Stock Appreciation Rights or effect the repricing of such Awards through cancellation and re-grants. To the extent required
under the rules of any securities exchange or market system on which the Stock is listed, to the extent determined by the Administrator to be required by the Code to ensure that Incentive Stock Options granted under the Plan are qualified under
Section 422 of the Code, Plan amendments shall be subject to approval by Company stockholders. Nothing in this Section 16 shall limit the Administrator’s authority to take any action permitted pursuant to Section 3(e) or 3(f).

  
 11 

 SECTION 17. STATUS OF PLAN 

With respect to the portion of any Award that has not been exercised and any payments in cash, Stock or other consideration not received by a
Participant, a Participant shall have no rights greater than those of a general creditor of the Company unless the Administrator shall otherwise expressly determine in connection with any Award or Awards. In its sole discretion, the Administrator
may authorize the creation of trusts or other arrangements to meet the Company’s obligations to deliver Stock or make payments with respect to Awards hereunder, provided that the existence of such trusts or other arrangements is consistent with
the foregoing sentence. 
 SECTION 18. GENERAL PROVISIONS 

(a)    No Distribution. The Administrator may require each person acquiring Stock pursuant to an Award to represent
to and agree with the Company in writing that such person is acquiring the shares without a view to distribution thereof. 

(b)    Issuance of Stock. To the extent certificated, stock certificates to Participants under this Plan shall be
deemed delivered for all purposes when the Company or a stock transfer agent of the Company shall have mailed such certificates in the United States mail, addressed to the Participant, at the Participant’s last known address on file with the
Company. Uncertificated Stock shall be deemed delivered for all purposes when the Company or a Stock transfer agent of the Company shall have given to the Participant by electronic mail (with proof of receipt) or by United States mail, addressed to
the Participant, at the Participant’s last known address on file with the Company, notice of issuance and recorded the issuance in its records (which may include electronic “book entry” records). Notwithstanding anything herein to the
contrary, the Company shall not be required to issue or deliver any evidence of book entry or certificates evidencing shares of Stock pursuant to the exercise or settlement of any Award, unless and until the Administrator has determined, with advice
of counsel (to the extent the Administrator deems such advice necessary or advisable), that the issuance and delivery is in compliance with all applicable laws, regulations of governmental authorities and, if applicable, the requirements of any
exchange on which the shares of Stock are listed, quoted or traded. Any Stock issued pursuant to the Plan shall be subject to any stop-transfer orders and other restrictions as the Administrator deems necessary or advisable to comply with federal,
state or foreign jurisdiction, securities or other laws, rules and quotation system on which the Stock is listed, quoted or traded. The Administrator may place legends on any Stock certificate or notations on any book entry to reference restrictions
applicable to the Stock. In addition to the terms and conditions provided herein, the Administrator may require that an individual make such reasonable covenants, agreements, and representations as the Administrator, in its discretion, deems
necessary or advisable in order to comply with any such laws, regulations, or requirements. The Administrator shall have the right to require any individual to comply with any timing or other restrictions with respect to the settlement or exercise
of any Award, including a window-period limitation, as may be imposed in the discretion of the Administrator. 

  
 12 

 (c)    Stockholder Rights. Until Stock is deemed delivered in
accordance with Section 18(b), no right to vote or receive dividends or any other rights of a stockholder will exist with respect to shares of Stock to be issued in connection with an Award, notwithstanding the exercise of a Stock Option or any
other action by the Participant with respect to an Award. 
 (d)    Other Compensation Arrangements; No Employment
Rights. Nothing contained in this Plan shall prevent the Board from adopting other or additional compensation arrangements, including trusts, and such arrangements may be either generally applicable or applicable only in specific cases. The
adoption of this Plan and the grant of Awards do not confer upon any employee any right to continued employment with the Company or any Subsidiary. 

(e)    Trading Policy Restrictions. Option exercises and other Awards under the Plan shall be subject to the
Company’s insider trading policies and procedures, as in effect from time to time. 
 (f)    Clawback
Policy. Awards under the Plan shall be subject to any of the Company’s clawback policies that may be adopted to comply with applicable law. 

SECTION 19. EFFECTIVE DATE OF PLAN 
 This
Plan shall become effective upon the date immediately preceding the Registration Date subject to prior stockholder approval in accordance with applicable state law, the Company’s bylaws and articles of incorporation, and applicable stock
exchange rules. No grants of Stock Options and other Awards may be made hereunder after the tenth anniversary of the Effective Date and no grants of Incentive Stock Options may be made hereunder after the tenth anniversary of the date the Plan is
approved by the Board. 
 SECTION 20. GOVERNING LAW 

This Plan and all Awards and actions taken thereunder shall be governed by, and construed in accordance with the General Corporation Law of the
State of Delaware as to matters within the scope thereof, and as to all other matters shall be governed by and construed in accordance with the internal laws of the Commonwealth of Massachusetts, applied without regard to conflict of law principles.

 SECTION 21. DEFINITIONS 
 Capitalized
terms in the Plan are defined below. 
 “Act” means the Securities Act of 1933, as amended, and the rules and
regulations thereunder. 
 “Administrator” means either the Board or the compensation committee of the Board or a similar
committee performing the functions of the compensation committee and which is comprised of not less than two Non-Employee Directors who are independent. 

  
 13 

 “Affiliate” means, at the time of determination, any “parent” or
“subsidiary” of the Company as such terms are defined in Rule 405 of the Act. The Board will have the authority to determine the time or times at which “parent” or “subsidiary” status is determined within the foregoing
definition. 
 “Award” or “Awards,” except where referring to a particular
category of grant under the Plan, shall include Incentive Stock Options, Non-Qualified Stock Options, Stock Appreciation Rights, Restricted Stock Units, Restricted Stock Awards, Unrestricted Stock Awards,
Cash-Based Awards, and Dividend Equivalent Rights. 
 “Award Agreement” means a written or electronic
document setting forth the terms and provisions applicable to an Award granted under the Plan. Each Award Agreement is subject to the terms and conditions of the Plan. 

“Board” means the Board of Directors of the Company. 

“Cash-Based Award” means an Award entitling the recipient to receive a cash-denominated payment. 

“Cause” is defined as a termination due to (i) any material breach by the Participant of any agreement
between the Participant and the Company; (ii) the conviction of, indictment for or plea of nolo contendere by the Participant to a felony or a crime involving moral turpitude; or (iii) material misconduct, including any material violation
of the Company’s Code of Conduct Policy, or willful and deliberate non-performance (other than by reason of disability) by the Participant of the Participant’s duties to the Company. 

“Code” means the Internal Revenue Code of 1986, as amended, and any successor Code, and related rules,
regulations and interpretations. 
 “Company” means Codiak BioSciences, Inc., a Delaware corporation. 

“Consultant” means a consultant or adviser who provides bona fide services to the Company or an
Affiliate as an independent contractor and who qualifies as a consultant or advisor under Instruction A.1.(a)(1) of Form S-8 under the Act. 

“Disability” means permanent and total disability under Section 22(e)(3) of the Code, as amended. 

“Dividend Equivalent Right” means an Award entitling the Participant to receive credits based on cash dividends
that would have been paid on the shares of Stock specified in the Dividend Equivalent Right (or other award to which it relates) if such shares had been issued to and held by the Participant. 

“Effective Date” means the date on which the Plan becomes effective as set forth in Section 19. 

“Equity Restructuring” means (i) any reorganization, recapitalization, reclassification, stock dividend,
stock split, reverse stock split or other similar change in the Company’s capital 

  
 14 

 
stock in which the outstanding shares of Stock are increased or decreased or are exchanged for a different number or kind of shares or other securities of the Company, or additional Stock or new
or different shares or other securities of the Company or other non-cash assets are distributed with respect to such shares of Stock or other securities, in each case, without receipt of consideration by the
Company, or (ii) any merger or consolidation or sale of all or substantially all of the assets of the Company, in which the outstanding shares of Stock are converted into or exchanged for other securities of the Company or any successor entity
(or a parent or subsidiary thereof). 
 “Exchange Act” means the Securities Exchange Act of 1934, as amended,
and the rules and regulations thereunder. 
 “Fair Market Value” of the Stock on any given date means the
fair market value of the Stock determined in good faith by the Administrator; provided, however, that if the Stock is listed on the National Association of Securities Dealers Automated Quotation System (“NASDAQ”), NASDAQ Global Market, The
New York Stock Exchange or another national securities exchange or traded on any established market, the determination shall be made by reference to market quotations. If there are no market quotations for such date, the determination shall be made
by reference to the last date preceding such date for which there are market quotations; provided further, however, that if the date for which Fair Market Value is determined is the Registration Date, the Fair Market Value shall be the “Price
to the Public” (or equivalent) set forth on the cover page for the final prospectus relating to the Company’s initial public offering. 

“Incentive Stock Option” means any Stock Option designated and qualified as an “incentive stock
option” as defined in Section 422 of the Code. 
 “Non-Employee Director”
means a member of the Board who is not also an employee of the Company or any Subsidiary. 

“Non-Qualified Stock Option” means any Stock Option that is not an Incentive Stock
Option. 
 “Option” or “Stock Option” means any option to purchase shares of
Stock granted pursuant to Section 5. 
 “Overall Share Limit” means the sum of (i) 1,043,402 shares of
Stock; (ii) any shares of Stock which are subject to Prior Plan awards which become available for issuance under the Plan pursuant to Section 3(c) and (iii) an annual increase on the first day of each calendar year beginning
January 1, 2021 and ending on and including January 1, 2030, equal to the lesser of (A) five percent (5%) of the aggregate number of shares of Stock outstanding on the final day of the immediately preceding calendar year and
(B) such lesser number of shares as determined by the Administrator.  

“Participant” means any employee, Non-Employee Director, or Consultant of the Company
or its Affiliates who receives an Award pursuant to this Plan. 
 “Plan” means this 2020 Stock Option and Incentive
Plan. 

  
 15 

 “Prior Plan” means the Company’s 2015 Stock Option and
Grant Plan. 
 “Registration Date” means the date upon which the registration statement on Form S-1 that is filed by the Company with respect to its initial public offering is declared effective by the Securities and Exchange Commission. 

“Restricted Shares” means the shares of Stock underlying a Restricted Stock Award that remain subject to a risk of forfeiture
or the Company’s right of repurchase. 
 “Restricted Stock Award” means an Award of Restricted Shares subject to such
restrictions and conditions as the Administrator may determine at the time of grant. 
 “Restricted Stock
Units” means an Award of stock units subject to such restrictions and conditions as the Administrator may determine at the time of grant. 

“Sale Event” shall mean (i) the sale of all or substantially all of the assets of the Company on a
consolidated basis to an unrelated person or entity, (ii) a merger, reorganization or consolidation pursuant to which the holders of the Company’s outstanding voting power and outstanding stock immediately prior to such transaction do not
own a majority of the outstanding voting power and outstanding stock or other equity interests of the resulting or successor entity (or its ultimate parent, if applicable) immediately upon completion of such transaction, (iii) the sale of all
of the Stock of the Company to an unrelated person, entity or group thereof acting in concert, or (iv) any other transaction in which the owners of the Company’s outstanding voting power immediately prior to such transaction do not own at
least a majority of the outstanding voting power of the Company or any successor entity immediately upon completion of the transaction other than as a result of the acquisition of securities directly from the Company. 

“Sale Price” means the value as determined by the Administrator of the consideration payable, or otherwise to be received by
stockholders, per share of Stock pursuant to a Sale Event. 
 “Section 409A” means
Section 409A of the Code and the regulations and other guidance promulgated thereunder. 
 “Service Relationship”
means any relationship as an employee, director or Consultant of the Company or any Affiliate (e.g., a Service Relationship shall be deemed to continue without interruption in the event an individual’s status changes from full-time employee
to part-time employee or Consultant). 
 “Stock” means the Common Stock, par value $0.0001 per share, of the
Company, subject to adjustments pursuant to Section 3. 
 “Stock Appreciation Right” means an Award
entitling the recipient to receive shares of Stock (or cash, to the extent explicitly provided for in the applicable Award Agreement) having a value equal to the excess of the Fair Market Value of the Stock on the date of exercise over the exercise
price of the Stock Appreciation Right multiplied by the number of shares of Stock with respect to which the Stock Appreciation Right shall have been exercised. 

  
 16 

 “Subsidiary” means any corporation or other entity (other
than the Company) in which the Company has at least a 50 percent interest, either directly or indirectly. 
 “Ten
Percent Owner” means an employee who owns or is deemed to own (by reason of the attribution rules of Section 424(d) of the Code) more than 10 percent of the combined voting power of all classes of stock of the Company or
any parent or subsidiary corporation. 
 “Unrestricted Stock Award” means an Award of shares of Stock free of any
restrictions. 
 DATE APPROVED BY BOARD OF DIRECTORS: September 17, 2020, and effective upon consummation of the Company’s initial public
offering. 
 DATE APPROVED BY STOCKHOLDERS: October 2, 2020, and effective upon consummation of the Company’s initial public offering. 

  
 17 

 INCENTIVE STOCK OPTION AGREEMENT 

UNDER THE CODIAK BIOSCIENCES, INC. 

2020 STOCK OPTION AND INCENTIVE PLAN 
  

					
	Name of Participant:	 	  
	 	
			
	No. of Option Shares:	 	                              	 	
			
	Option Exercise Price per Share:	 	$                            	 	
		 	[FMV on Grant Date (110% of FMV if a 10% owner)]
			
	Grant Date:	 	                              	 	
			
	Expiration Date:	 	                              	 	
		 	[up to 10 years (5 if a 10% owner)]	 	

 The Company has granted to the participant listed above (the “Participant”) the stock option
described herein (the “Stock Option”), subject to the terms and conditions of the Codiak BioSciences, Inc. 2020 Stock Option and Incentive Plan (the “Plan”) and this Stock Option Agreement (the
“Agreement”). 
 1.    Vesting and Exercisability Schedule. No portion of this Stock Option may
be exercised until such portion shall have vested and become exercisable. Except as set forth below, and subject to the discretion of the Administrator, this Stock Option shall vest and become exercisable according to the schedule below so long as
Participant remains an employee of the Company or a Subsidiary on such dates: 
  

			
	 Number of
Option Shares
Exercisable
	  	 Exercisability Date

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

 * Max. of $100,000 per yr. 

Once exercisable, this Stock Option shall continue to be exercisable at any time prior to the close of business on the Expiration Date,
subject to the provisions in this Agreement and of the Plan. 

 2.    Manner of Exercise. 

(a)    The Participant may exercise this Stock Option by providing written notice to the Company as set forth in the Plan.

 The transfer to the Participant of the shares of Stock purchased upon exercise of this Stock Option will be contingent upon (i) the
Company’s receipt from the Participant of the full purchase price for the Option Shares, as set forth above, (ii) the fulfillment of any other requirements contained herein or in the Plan or in any other agreement or provision of laws, and
(iii) the receipt by the Company of any agreement, statement or other evidence that the Company may require to satisfy itself that the issuance of Stock to be purchased pursuant to the exercise of Stock Options under the Plan and any subsequent
resale of the shares of Stock will be in compliance with applicable laws and regulations. In the event the Participant chooses to pay the purchase price by previously-owned shares of Stock through the attestation method, the number of shares of
Stock transferred to the Participant upon the exercise of the Stock Option shall be net of the Shares attested to. 

(b)    The shares of Stock purchased upon exercise of this Stock Option shall be transferred to the Participant, subject
to verification by the Administrator of compliance with the terms of this Agreement and the Plan. The determination of the Administrator as to such compliance shall be final and binding on the Participant. The Participant shall not be deemed to be
the holder of, or to have any of the rights of a holder with respect to, any shares of Stock subject to this Stock Option unless and until this Stock Option shall have been validly exercised and the shares have been transferred to the Participant.
The minimum number of shares with respect to which this Stock Option may be exercised at any one time shall be 100 shares, unless the number of shares with respect to which this Stock Option is being exercised is the total number of shares subject
to exercise under this Stock Option at the time. 
 (c)    Notwithstanding any other provision hereof or of the Plan, no
portion of this Stock Option shall be exercisable after the Expiration Date. 
 3.    Termination of Employment.
If the Participant’s employment by the Company or a Subsidiary is terminated, the period within which to exercise the Stock Option may be subject to earlier termination as set forth below. 

(a)    Termination Due to Death. If the Participant’s employment terminates by reason of death, any portion of
this Stock Option outstanding on such date, to the extent exercisable on the date of death, may thereafter be exercised by the Participant’s legal representative or legatee for a period of 12 months from the date of death or until the
Expiration Date, if earlier; provided that any portion of this Stock Option that is unvested as of the date of Participant’s death will accelerate and become vested and exercisable upon the date of Participant’s death. 

(b)    Termination Due to Disability. If the Participant’s employment terminates by reason of Disability (as
determined by the Administrator), any portion of this Stock Option outstanding on such date, to the extent exercisable on the date of such termination of employment, may thereafter be exercised by the Participant for a period of 12 months from the

  
 2 

 
date of termination or until the Expiration Date, if earlier; provided that any portion of this Stock Option that is not exercisable on the date of termination shall terminate immediately and be
of no further force or effect. 
 (c)    Termination for Cause. If the Participant’s employment terminates
for Cause as defined in the Plan, any portion of this Stock Option outstanding on such date shall be forfeited and terminate immediately. 

(d)    Other Termination. If the Participant’s employment terminates for any reason other than death,
Disability or Cause any portion of this Stock Option outstanding on such date may be exercised, for a period of ninety (90) days from the date of termination or until the Expiration Date, if earlier; provided that any portion of this Stock
Option that is not exercisable on the date of termination shall terminate immediately and be of no further force or effect. 
 The
Administrator’s determination of the reason for termination of the Participant’s employment shall be conclusive and binding on the Participant and his or her representatives or legatees. 

4.    Incorporation of Plan. Notwithstanding anything herein to the contrary, this Stock Option shall be subject to
and governed by all the terms and conditions of the Plan, including the powers of the Administrator set forth in Section 2(b) of the Plan. Capitalized terms in this Agreement shall have the meaning specified in the Plan, unless a different
meaning is specified herein. 
 5.    Transferability. This Agreement is personal to the Participant, is non-assignable and is not transferable in any manner, by operation of law or otherwise, other than by will or the laws of descent and distribution. This Stock Option is exercisable, during the Participant’s
lifetime, only by the Participant, and thereafter, only by the Participant’s legal representative or legatee. 

6.    Status of the Stock Option. This Stock Option is intended to qualify as an “incentive stock option”
under Section 422 of the Code, but the Company does not represent or warrant that this Stock Option qualifies as such. The Participant should consult with his or her own tax advisors regarding the tax effects of this Stock Option and the
requirements necessary to obtain favorable income tax treatment under Section 422 of the Code, including, but not limited to, holding period requirements. To the extent any portion of this Stock Option does not so qualify as an “incentive
stock option,” such portion shall be deemed to be a non-qualified stock option. If the Participant intends to dispose or does dispose (whether by sale, gift, transfer or otherwise) of any Option Shares
within the one-year period beginning on the date after the transfer of such shares to him or her, or within the two-year period beginning on the day after the grant of
this Stock Option, he or she will so notify the Company within 30 days after such disposition. 
 7.    Tax
Withholding. The Participant shall, not later than the date as of which the exercise of this Stock Option becomes a taxable event for Federal income tax purposes, pay to the Company or make arrangements satisfactory to the Company for payment of
any Federal, state, and local taxes required by law to be withheld on account of such taxable event. The 

  
 3 

 
Company shall have the authority to cause the required tax withholding obligation to be satisfied, in whole or in part, by withholding from shares of Stock to be issued to the Participant a
number of shares of Stock with an aggregate Fair Market Value that would satisfy the withholding amount due. 

8.    No Obligation to Continue Employment. Neither the Company nor any Subsidiary is obligated by or as a result
of the Plan or this Agreement to continue the Participant in employment and neither the Plan nor this Agreement shall interfere in any way with the right of the Company or any Subsidiary to terminate the employment of the Participant at any time.

 9.    Integration. This Agreement constitutes the entire agreement between the parties with respect to this
Stock Option and supersedes all prior agreements and discussions between the parties concerning such subject matter. 

10.    Data Privacy Consent. In order to administer the Plan and this Agreement and to implement or structure
future equity grants, the Company, its subsidiaries and affiliates and certain agents thereof (together, the “Relevant Companies”) may process any and all personal or professional data, including but not limited to Social Security
or other identification number, home address and telephone number, date of birth and other information that is necessary or desirable for the administration of the Plan and/or this Agreement (the “Relevant Information”). By entering
into this Agreement, the Participant (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information; (ii) waives any privacy rights the Participant may have with respect to the
Relevant Information; (iii) authorizes the Relevant Companies to store and transmit such information in electronic form; and (iv) authorizes the transfer of the Relevant Information to any jurisdiction in which the Relevant Companies
consider appropriate. The Participant shall have access to, and the right to change, the Relevant Information. Relevant Information will only be used in accordance with applicable law. 

  
 4 

 11.    Notices. Notices hereunder shall be mailed or delivered to
the Company at its principal place of business and shall be mailed or delivered to the Participant at the address on file with the Company or, in either case, at such other address as one party may subsequently furnish to the other party in writing.

  

									
		 		 	     CODIAK BIOSCIENCES, INC.	  	

									
					
		 		 	By:	  	  
	  	
		 		 		  	Title:	  	

							
	
	Electronic acceptance of this Agreement pursuant to the Company’s instructions or your signature below (including through an online acceptance process) shall constitute your acceptance of the terms and conditions in
this agreement.
				
	Dated:
                                         
           	 		  	  
	  	
		 		  	Participant’s Signature	  	
				
		 	            	  	Participant’s name and address:	  	
				
		 		  	  
	  	
				
		 		  	  
	  	
				
		 		  	  
	  	

  
 5 

 NON-QUALIFIED STOCK OPTION AGREEMENT 

FOR COMPANY EMPLOYEES 

UNDER THE CODIAK BIOSCIENCES, INC. 

2020 STOCK OPTION AND INCENTIVE PLAN 
  

					
	Name of Participant:	 	  
	 	
			
	No. of Option Shares:	 	                              	 	
			
	Option Exercise Price per Share:	 	$                            	 	
		 	[FMV on Grant Date]
			
	Grant Date:	 	                              	 	
			
	Expiration Date:	 	                              	 	
		 	[No more than 10 years]	 	

 The Company has granted to the participant listed above (the “Participant”) the stock option described herein
(the “Stock Option”), subject to the terms and conditions of the Codiak BioSciences, Inc. 2020 Stock Option and Incentive Plan (the “Plan”) and this Stock Option Agreement (the
“Agreement”). This Stock Option is not intended to be an “incentive stock option” under Section 422 of the Code. 

1.    Vesting and Exercisability Schedule. No portion of this Stock Option may be exercised until such portion
shall have vested and become exercisable. Except as set forth below, and subject to the discretion of the Administrator, this Stock Option shall vest and become exercisable according to the schedule below so long as Participant remains an employee
of the Company or a Subsidiary on such dates: 
  

			
	 Number of
Option Shares
Exercisable
	  	 Exercisability Date

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

 Once exercisable, this Stock Option shall continue to be exercisable at any time prior to the close of
business on the Expiration Date, subject to the provisions in this Agreement and of the Plan. 

 2.    Manner of Exercise. 

(a)    The Participant may exercise this Stock Option by providing written notice to the Company as set forth in the Plan.

 The transfer to the Participant of the shares of Stock purchased upon exercise of this Stock Option will be contingent upon (i) the
Company’s receipt from the Participant of the full purchase price for the Option Shares, as set forth above, (ii) the fulfillment of any other requirements contained herein or in the Plan or in any other agreement or provision of laws, and
(iii) the receipt by the Company of any agreement, statement or other evidence that the Company may require to satisfy itself that the issuance of Stock to be purchased pursuant to the exercise of Stock Options under the Plan and any subsequent
resale of the shares of Stock will be in compliance with applicable laws and regulations. In the event the Participant chooses to pay the purchase price by previously-owned shares of Stock through the attestation method, the number of shares of
Stock transferred to the Participant upon the exercise of the Stock Option shall be net of the Shares attested to. 

(b)    The shares of Stock purchased upon exercise of this Stock Option shall be transferred to the Participant, subject
to verification by the Administrator of compliance with the terms of this Agreement and the Plan. The determination of the Administrator as to such compliance shall be final and binding on the Participant. The Participant shall not be deemed to be
the holder of, or to have any of the rights of a holder with respect to, any shares of Stock subject to this Stock Option unless and until this Stock Option shall have been validly exercised and the shares have been transferred to the Participant.
The minimum number of shares with respect to which this Stock Option may be exercised at any one time shall be 100 shares, unless the number of shares with respect to which this Stock Option is being exercised is the total number of shares subject
to exercise under this Stock Option at the time. 
 (c)    Notwithstanding any other provision hereof or of the Plan, no
portion of this Stock Option shall be exercisable after the Expiration Date. 
 3.    Termination of Employment.
If the Participant’s employment by the Company or a Subsidiary is terminated, the period within which to exercise the Stock Option may be subject to earlier termination as set forth below. 

(a)    Termination Due to Death. If the Participant’s employment terminates by reason of death, any portion of
this Stock Option outstanding on such date, to the extent exercisable on the date of death, may thereafter be exercised by the Participant’s legal representative or legatee for a period of 12 months from the date of death or until the
Expiration Date, if earlier; provided that any portion of this Stock Option that is unvested as of the date of Participant’s death will accelerate and become vested and exercisable upon the date of Participant’s death. 

(b)    Termination Due to Disability. If the Participant’s employment terminates by reason of Disability (as
determined by the Administrator), any portion of this Stock Option outstanding on such date, to the extent exercisable on the date of such termination of employment, may thereafter be exercised by the Participant for a period of 12 months from the

  
 2 

 
date of termination or until the Expiration Date, if earlier; provided that any portion of this Stock Option that is not exercisable on the date of termination shall terminate immediately and be
of no further force or effect. 
 (c)    Termination for Cause. If the Participant’s employment terminates
for Cause as defined in the Plan, any portion of this Stock Option outstanding on such date shall be forfeited and terminate immediately. 

(d)    Other Termination. If the Participant’s employment terminates for any reason other than death,
Disability or Cause any portion of this Stock Option outstanding on such date may be exercised, for a period of ninety (90) days from the date of termination or until the Expiration Date, if earlier; provided that any portion of this Stock
Option that is not exercisable on the date of termination shall terminate immediately and be of no further force or effect. 
 The
Administrator’s determination of the reason for termination of the Participant’s employment shall be conclusive and binding on the Participant and his or her representatives or legatees. 

4.    Incorporation of Plan. Notwithstanding anything herein to the contrary, this Stock Option shall be subject to
and governed by all the terms and conditions of the Plan, including the powers of the Administrator set forth in Section 2(b) of the Plan. Capitalized terms in this Agreement shall have the meaning specified in the Plan, unless a different
meaning is specified herein. 
 5.    Transferability. This Agreement is personal to the Participant, is non-assignable and is not transferable in any manner, by operation of law or otherwise, other than by will or the laws of descent and distribution. This Stock Option is exercisable, during the Participant’s
lifetime, only by the Participant, and thereafter, only by the Participant’s legal representative or legatee. 

6.    Tax Withholding. The Participant shall, not later than the date as of which the exercise of this Stock Option
becomes a taxable event for Federal income tax purposes, pay to the Company or make arrangements satisfactory to the Company for payment of any Federal, state, and local taxes required by law to be withheld on account of such taxable event. The
Company shall have the authority to cause the required tax withholding obligation to be satisfied, in whole or in part, by withholding from shares of Stock to be issued to the Participant a number of shares of Stock with an aggregate Fair Market
Value that would satisfy the withholding amount due. 
 7.    No Obligation to Continue Employment. Neither the
Company nor any Subsidiary is obligated by or as a result of the Plan or this Agreement to continue the Participant in employment and neither the Plan nor this Agreement shall interfere in any way with the right of the Company or any Subsidiary to
terminate the employment of the Participant at any time. 
 8.    Integration. This Agreement constitutes the
entire agreement between the parties with respect to this Stock Option and supersedes all prior agreements and discussions between the parties concerning such subject matter. 

  
 3 

 9.    Data Privacy Consent. In order to administer the Plan and
this Agreement and to implement or structure future equity grants, the Company, its subsidiaries and affiliates and certain agents thereof (together, the “Relevant Companies”) may process any and all personal or professional data,
including but not limited to Social Security or other identification number, home address and telephone number, date of birth and other information that is necessary or desirable for the administration of the Plan and/or this Agreement (the
“Relevant Information”). By entering into this Agreement, the Participant (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information; (ii) waives any privacy
rights the Participant may have with respect to the Relevant Information; (iii) authorizes the Relevant Companies to store and transmit such information in electronic form; and (iv) authorizes the transfer of the Relevant Information to
any jurisdiction in which the Relevant Companies consider appropriate. The Participant shall have access to, and the right to change, the Relevant Information. Relevant Information will only be used in accordance with applicable law. 

10.    Notices. Notices hereunder shall be mailed or delivered to the Company at its principal place of business
and shall be mailed or delivered to the Participant at the address on file with the Company or, in either case, at such other address as one party may subsequently furnish to the other party in writing. 

 

									
		 		 	     CODIAK BIOSCIENCES, INC.	  	

									
					
		 		 	By:	  	  
	  	
		 		 		  	Title:	  	

							
	
	Electronic acceptance of this Agreement pursuant to the Company’s instructions or your signature below (including through an online acceptance process) shall constitute your acceptance of the terms and conditions in
this agreement.
				
	Dated:
                                         
           	 		  	  
	  	
		 		  	Participant’s Signature	  	
				
		 	            	  	Participant’s name and address:	  	
				
		 		  	  
	  	
				
		 		  	  
	  	
				
		 		  	  
	  	

  
 4 

 NON-QUALIFIED STOCK OPTION AGREEMENT 

FOR NON-EMPLOYEE DIRECTORS 

UNDER THE CODIAK BIOSCIENCES, INC. 

2020 STOCK OPTION AND INCENTIVE PLAN 
  

					
	Name of Participant:	 	  
	 	
			
	No. of Option Shares:	 	                              	 	
			
	Option Exercise Price per Share:	 	$                            	 	
		 	[FMV on Grant Date]
			
	Grant Date:	 	                              	 	
			
	Expiration Date:	 	                              	 	
		 	[No more than 10 years]	 	

 The Company has granted to the participant listed above (the “Participant”) the stock option
described herein (the “Stock Option”), subject to the terms and conditions of the Codiak BioSciences, Inc. 2020 Stock Option and Incentive Plan (the “Plan”) and this Stock Option Agreement (the
“Agreement”). This Stock Option is not intended to be an “incentive stock option” under Section 422 of the Code. 

1.    Vesting and Exercisability Schedule. No portion of this Stock Option may be exercised until such portion
shall have vested and become exercisable. Except as set forth below, and subject to the discretion of the Administrator, this Stock Option shall vest and become exercisable according to the schedule below so long as Participant continues to have a
Service Relationship on such dates: 
  

			
	 Number of
Option Shares
Exercisable
	  	 Exercisability Date

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

 Notwithstanding the foregoing, this Stock Option will fully vest and become immediately exercisable upon a
Sale Event. Once exercisable, this Stock Option shall continue to be exercisable at any time prior to the close of business on the Expiration Date, subject to the provisions in this Agreement and of the Plan. 

 2.    Manner of Exercise. 

(a)    The Participant may exercise this Stock Option by providing written notice to the Company as set forth in the Plan.

 The transfer to the Participant of the shares of Stock purchased upon exercise of this Stock Option will be contingent upon (i) the
Company’s receipt from the Participant of the full purchase price for the Option Shares, as set forth above, (ii) the fulfillment of any other requirements contained herein or in the Plan or in any other agreement or provision of laws, and
(iii) the receipt by the Company of any agreement, statement or other evidence that the Company may require to satisfy itself that the issuance of Stock to be purchased pursuant to the exercise of Stock Options under the Plan and any subsequent
resale of the shares of Stock will be in compliance with applicable laws and regulations. In the event the Participant chooses to pay the purchase price by previously-owned shares of Stock through the attestation method, the number of shares of
Stock transferred to the Participant upon the exercise of the Stock Option shall be net of the Shares attested to. 

(b)    The shares of Stock purchased upon exercise of this Stock Option shall be transferred to the Participant, subject
to verification by the Administrator of compliance with the terms of this Agreement and the Plan. The determination of the Administrator as to such compliance shall be final and binding on the Participant. The Participant shall not be deemed to be
the holder of, or to have any of the rights of a holder with respect to, any shares of Stock subject to this Stock Option unless and until this Stock Option shall have been validly exercised and the shares have been transferred to the Participant.
The minimum number of shares with respect to which this Stock Option may be exercised at any one time shall be 100 shares, unless the number of shares with respect to which this Stock Option is being exercised is the total number of shares subject
to exercise under this Stock Option at the time. 
 (c)    Notwithstanding any other provision hereof or of the Plan, no
portion of this Stock Option shall be exercisable after the Expiration Date. 
 3.    Termination of Service
Relationship. If the Participant’s Service Relationship is terminated, the period within which to exercise the Stock Option may be subject to earlier termination as set forth below. 

(a)    Termination Due to Death. If the Participant’s Service Relationship terminates by reason of the
Participant’s death, any portion of this Stock Option outstanding on such date, to the extent exercisable on the date of termination, may thereafter be exercised by the Participant’s legal representative or legatee for a period of 12
months from the date of termination or until the Expiration Date, if earlier; provided that any portion of this Stock Option that is unvested as of the date of Participant’s death will accelerate and become vested and exercisable upon the date
of Participant’s death. 
 (b)    Other Termination. If the Participant’s Service Relationship
terminates for any reason other than the Participant’s death, any portion of this Stock Option outstanding on such date may be exercised, to the extent exercisable on the date of such termination of Service Relationship, for a period of six
months from the date of termination or until the Expiration Date, if earlier; provided that any portion of this Stock Option that is not exercisable on the date of termination shall terminate immediately and be of no further force or effect. 

  
 2 

 4.    Incorporation of Plan. Notwithstanding anything herein to
the contrary, this Stock Option shall be subject to and governed by all the terms and conditions of the Plan, including the powers of the Administrator set forth in Section 2(b) of the Plan. Capitalized terms in this Agreement shall have the
meaning specified in the Plan, unless a different meaning is specified herein. 
 5.    Transferability. This
Agreement is personal to the Participant, is non-assignable and is not transferable in any manner, by operation of law or otherwise, other than by will or the laws of descent and distribution. This Stock
Option is exercisable, during the Participant’s lifetime, only by the Participant, and thereafter, only by the Participant’s legal representative or legatee. 

6.    No Obligation to Continue as a Director. Neither the Plan nor this Stock Option confers upon the Participant
any rights with respect to continuance as a Director or continuance of any other Service Relationship. 

7.    Integration. This Agreement constitutes the entire agreement between the parties with respect to this Stock
Option and supersedes all prior agreements and discussions between the parties concerning such subject matter. 

8.    Data Privacy Consent. In order to administer the Plan and this Agreement and to implement or structure future
equity grants, the Company, its subsidiaries and affiliates and certain agents thereof (together, the “Relevant Companies”) may process any and all personal or professional data, including but not limited to Social Security or other
identification number, home address and telephone number, date of birth and other information that is necessary or desirable for the administration of the Plan and/or this Agreement (the “Relevant Information”). By entering into
this Agreement, the Participant (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information; (ii) waives any privacy rights the Participant may have with respect to the Relevant
Information; (iii) authorizes the Relevant Companies to store and transmit such information in electronic form; and (iv) authorizes the transfer of the Relevant Information to any jurisdiction in which the Relevant Companies consider
appropriate. The Participant shall have access to, and the right to change, the Relevant Information. Relevant Information will only be used in accordance with applicable law. 

  
 3 

 9.    Notices. Notices hereunder shall be mailed or delivered to
the Company at its principal place of business and shall be mailed or delivered to the Participant at the address on file with the Company or, in either case, at such other address as one party may subsequently furnish to the other party in writing.

  

									
		 		 	     CODIAK BIOSCIENCES, INC.	  	

									
					
		 		 	By:	  	  
	  	
		 		 		  	Title:	  	

							
	
	Electronic acceptance of this Agreement pursuant to the Company’s instructions or your signature below (including through an online acceptance process) shall constitute your acceptance of the terms and conditions in
this agreement.
				
	Dated:
                                         
           	 		  	  
	  	
		 		  	Participant’s Signature	  	
				
		 	            	  	Participant’s name and address:	  	
				
		 		  	  
	  	
				
		 		  	  
	  	
				
		 		  	  
	  	

  
 4 

 RESTRICTED STOCK AWARD AGREEMENT 

UNDER THE CODIAK BIOSCIENCES, INC. 

2020 STOCK OPTION AND INCENTIVE PLAN 
  

					
	Name of Participant:	 	  
	 	
			
	No. of Shares:	 	                              	 	
			
	Grant Date:	 	                              	 	

 The Company has granted to the participant listed above (the “Participant”) the number of shares of Stock
listed above (the “Restricted Stock”), subject to the terms and conditions of the Codiak BioSciences, Inc. 2020 Stock Option and Incentive Plan (the “Plan”) and this Restricted Stock Award Agreement (the
“Agreement”). 
 1.    Award. The shares of Restricted Stock awarded hereunder shall be issued
and held by the Company’s transfer agent in book entry form, and the Participant’s name shall be entered as the stockholder of record on the books of the Company. Thereupon, the Participant shall have all the rights of a stockholder with
respect to such shares, including voting and dividend rights, subject, however, to the restrictions and conditions specified in Paragraph 2 below. The Participant shall (i) sign and deliver to the Company a copy of this Award Agreement and
(ii) deliver to the Company a stock power endorsed in blank. 
 2.    Restrictions and Conditions. 

(a)    Any book entries for the shares of Restricted Stock granted herein shall bear an appropriate legend, as determined
by the Administrator in its sole discretion, to the effect that such shares are subject to restrictions as set forth herein and in the Plan. 

(b)    Shares of Restricted Stock granted herein may not be sold, assigned, transferred, pledged or otherwise encumbered
or disposed of by the Participant prior to vesting. 
 (c)    If the Participant’s employment with the Company and
its Subsidiaries terminates by reason of death, all vesting conditions set forth in Paragraph 3 below will accelerate and become vested upon the date of the Participant’s death. If the Participant’s employment with the Company and its
Subsidiaries is voluntarily or involuntarily terminated for any reason other than death prior to vesting of shares of Restricted Stock granted herein, all shares of Restricted Stock shall immediately and automatically be forfeited and returned to
the Company. 
 3.    Vesting of Restricted Stock. The restrictions and conditions in Paragraph 2 of this
Agreement shall lapse on the vesting date or dates specified in the following schedule so long as the Participant remains an employee of the Company or a Subsidiary on such dates. If a series of vesting dates is specified, then the restrictions and
conditions in Paragraph 2 shall lapse only with respect to the number of shares of Restricted Stock specified as vested on such date. 

			
	 Number
of Shares Vested
	  	 Vesting Date

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

 Subsequent to such vesting date or dates, the shares of Stock on which all restrictions and conditions have
lapsed shall no longer be deemed Restricted Stock. The Administrator may at any time accelerate the vesting schedule specified in this Paragraph 3. 

4.    Dividends. Dividends on shares of Restricted Stock shall be paid currently to the Participant; provided that
if the vesting conditions in Paragraph 3 include the attainment of performance goals, any dividends paid by the Company during the performance period shall accrue and shall not be paid to the Participant until and to the extent the performance goals
are met. 
 5.    Incorporation of Plan. Notwithstanding anything herein to the contrary, this Award shall be
subject to and governed by all the terms and conditions of the Plan, including the powers of the Administrator set forth in Section 2(b) of the Plan. Capitalized terms in this Agreement shall have the meaning specified in the Plan, unless a
different meaning is specified herein. 
 6.    Transferability. This Agreement is personal to the Participant,
is non-assignable and is not transferable in any manner, by operation of law or otherwise, other than by will or the laws of descent and distribution. 

7.    Tax Withholding. The Participant shall, not later than the date as of which the receipt of this Award becomes
a taxable event for Federal income tax purposes, pay to the Company or make arrangements satisfactory to the Company for payment of any Federal, state, and local taxes required by law to be withheld on account of such taxable event. Except in the
case where an election is made pursuant to Paragraph 8 below, the Company shall have the authority to cause the required tax withholding obligation to be satisfied, in whole or in part, by withholding from shares of Stock to be issued or released by
the transfer agent a number of shares of Stock with an aggregate Fair Market Value that would satisfy the withholding amount due. 

8.    Election Under Section 83(b). The Participant and the Company hereby agree that the
Participant may, within 30 days following the Grant Date of this Award, file with the Internal Revenue Service and the Company an election under Section 83(b) of the Code. In the event the Participant makes such an election, he or she agrees to
provide a copy of the election to the Company. The Participant acknowledges that he or she is responsible for obtaining the advice of his or her tax advisors with regard to the Section 83(b) election and that he or she is relying solely on such
advisors and not on any statements or representations of the Company or any of its agents with regard to such election. 

  
 2 

 9.    No Obligation to Continue Employment. Neither the Company
nor any Subsidiary is obligated by or as a result of the Plan or this Agreement to continue the Participant in employment and neither the Plan nor this Agreement shall interfere in any way with the right of the Company or any Subsidiary to terminate
the employment of the Participant at any time. 
 10.    Integration. This Agreement constitutes the entire
agreement between the parties with respect to this Award and supersedes all prior agreements and discussions between the parties concerning such subject matter. 

11.    Data Privacy Consent. In order to administer the Plan and this Agreement and to implement or structure
future equity grants, the Company, its subsidiaries and affiliates and certain agents thereof (together, the “Relevant Companies”) may process any and all personal or professional data, including but not limited to Social Security
or other identification number, home address and telephone number, date of birth and other information that is necessary or desirable for the administration of the Plan and/or this Agreement (the “Relevant Information”). By entering
into this Agreement, the Participant (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information; (ii) waives any privacy rights the Participant may have with respect to the
Relevant Information; (iii) authorizes the Relevant Companies to store and transmit such information in electronic form; and (iv) authorizes the transfer of the Relevant Information to any jurisdiction in which the Relevant Companies
consider appropriate. The Participant shall have access to, and the right to change, the Relevant Information. Relevant Information will only be used in accordance with applicable law. 

  
 3 

 12.    Notices. Notices hereunder shall be mailed or delivered to
the Company at its principal place of business and shall be mailed or delivered to the Participant at the address on file with the Company or, in either case, at such other address as one party may subsequently furnish to the other party in writing.

  

									
		 		 	     CODIAK BIOSCIENCES, INC.	  	

									
					
		 		 	By:	  	  
	  	
		 		 		  	Title:	  	

							
	
	Electronic acceptance of this Agreement pursuant to the Company’s instructions or your signature below (including through an online acceptance process) shall constitute your acceptance of the terms and conditions in
this agreement.
				
	Dated:
                                         
           	 		  	  
	  	
		 		  	Participant’s Signature	  	
				
		 	            	  	Participant’s name and address:	  	
				
		 		  	  
	  	
				
		 		  	  
	  	
				
		 		  	  
	  	

  
 4 

 RESTRICTED STOCK UNIT AWARD AGREEMENT 

FOR NON-EMPLOYEE DIRECTORS 

UNDER THE CODIAK BIOSCIENCES, INC. 

2020 STOCK OPTION AND INCENTIVE PLAN 
  

					
	Name of Participant:	 	  
	 	
			
	 No. of Restricted Stock Units:
	 	                              	 	
			
	Grant Date:	 	                              	 	

 The Company has granted to the participant listed above (the “Participant”) the award of the number of
Restricted Stock Units listed above (the “Award”), subject to the terms and conditions of the Codiak BioSciences, Inc. 2020 Stock Option and Incentive Plan (the “Plan”) and this Restricted Stock Unit Award Agreement
(the “Agreement”). Each Restricted Stock Unit shall relate to one share of Stock. 

1.    Restrictions on Transfer of Award. This Award may not be sold, transferred, pledged, assigned or otherwise
encumbered or disposed of by the Participant, and any shares of Stock issuable with respect to the Award may not be sold, transferred, pledged, assigned or otherwise encumbered or disposed of until (i) the Restricted Stock Units have vested as
provided in Paragraph 2 of this Agreement and (ii) shares of Stock have been issued to the Participant in accordance with the terms of the Plan and this Agreement. 

2.    Vesting of Restricted Stock Units. The restrictions and conditions of Paragraph 1 of this Agreement
shall lapse on the vesting date or dates specified in the following schedule so long as the Participant continues to have a Service Relationship on such dates. If a series of vesting dates is specified, then the restrictions and conditions in
Paragraph 1 shall lapse only with respect to the number of Restricted Stock Units specified as vested on such date. 
  

			
	 Number of
Restricted Stock Units
Vested
	  	 Vesting Date

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

 Notwithstanding the foregoing, this Award and all Restricted Stock Units will fully vest upon a Sale Event.
The Administrator may at any time accelerate the vesting schedule specified in this Paragraph 2. 
 3.    Termination
of Service Relationship. If the Participant’s Service Relationship terminates by reason of death, this Award and all vesting conditions set forth in Paragraph 2 above will accelerate and become vested upon the date of the Participant’s
death. If the Participant’s Service Relationship terminates for any reason other than death prior to the 

 
satisfaction of the vesting conditions set forth in Paragraph 2 above, any Restricted Stock Units that have not vested as of such date shall automatically and without notice terminate and be
forfeited, and neither the Participant nor any of his or her successors, heirs, assigns, or personal representatives will thereafter have any further rights or interests in such unvested Restricted Stock Units. 

4.    Issuance of Shares of Stock. As soon as practicable following each vesting date (but in no event later than
two and one-half months after the end of the year in which the vesting date occurs), the Company shall issue to the Participant (or the Participant’s estate) the number of shares of Stock equal to the
aggregate number of Restricted Stock Units that have vested pursuant to Paragraph 2 of this Agreement on such date and the Participant shall thereafter have all the rights of a stockholder of the Company with respect to such shares. 

5.    Incorporation of Plan. Notwithstanding anything herein to the contrary, this Agreement shall be subject to
and governed by all the terms and conditions of the Plan, including the powers of the Administrator set forth in Section 2(b) of the Plan. Capitalized terms in this Agreement shall have the meaning specified in the Plan, unless a different
meaning is specified herein. 
 6.    Section 409A of the Code. This Agreement shall be interpreted in such a
manner that all provisions relating to the settlement of the Award are exempt from the requirements of Section 409A of the Code as “short-term deferrals” as described in Section 409A of the Code. 

7.    No Obligation to Continue as a Director. Neither the Plan nor this Award confers upon the Participant any
rights with respect to continuance as a Director. 
 8.    Integration. This Agreement constitutes the entire
agreement between the parties with respect to this Award and supersedes all prior agreements and discussions between the parties concerning such subject matter. 

9.    Data Privacy Consent. In order to administer the Plan and this Agreement and to implement or structure future
equity grants, the Company, its subsidiaries and affiliates and certain agents thereof (together, the “Relevant Companies”) may process any and all personal or professional data, including but not limited to Social Security or other
identification number, home address and telephone number, date of birth and other information that is necessary or desirable for the administration of the Plan and/or this Agreement (the “Relevant Information”). By entering into
this Agreement, the Participant (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information; (ii) waives any privacy rights the Participant may have with respect to the Relevant
Information; (iii) authorizes the Relevant Companies to store and transmit such information in electronic form; and (iv) authorizes the transfer of the Relevant Information to any jurisdiction in which the Relevant Companies consider
appropriate. The Participant shall have access to, and the right to change, the Relevant Information. Relevant Information will only be used in accordance with applicable law. 

10.    Notices. Notices hereunder shall be mailed or delivered to the Company at its principal place of business
and shall be mailed or delivered to the Participant at the address on file with the Company or, in either case, at such other address as one party may subsequently furnish to the other party in writing. 

  
 2 

									
		 		 	     CODIAK BIOSCIENCES, INC.	  	

									
					
		 		 	By:	  	  
	  	
		 		 		  	Title:	  	

							
	
	Electronic acceptance of this Agreement pursuant to the Company’s instructions or your signature below (including through an online acceptance process) shall constitute your acceptance of the terms and conditions in
this agreement.
				
	Dated:
                                         
           	 		  	  
	  	
		 		  	Participant’s Signature	  	
				
		 	            	  	Participant’s name and address:	  	
				
		 		  	  
	  	
				
		 		  	  
	  	
				
		 		  	  
	  	

  
 3 

 RESTRICTED STOCK UNIT AWARD AGREEMENT 

FOR COMPANY EMPLOYEES 

UNDER THE CODIAK BIOSCIENCES, INC. 

2020 STOCK OPTION AND INCENTIVE PLAN 
  

					
	Name of Participant:	 	  
	 	
			
	 No. of Restricted Stock Units:
	 	                              	 	
			
	Grant Date:	 	                              	 	

 The Company has granted to the participant listed above (the “Participant”) the award of the number of
Restricted Stock Units listed above (the “Award”), subject to the terms and conditions of the Codiak BioSciences, Inc. 2020 Stock Option and Incentive Plan (the “Plan”) and this Restricted Stock Unit Award Agreement
(the “Agreement”). Each Restricted Stock Unit shall relate to one share of Stock. 

1.    Restrictions on Transfer of Award. This Award may not be sold, transferred, pledged, assigned or otherwise
encumbered or disposed of by the Participant, and any shares of Stock issuable with respect to the Award may not be sold, transferred, pledged, assigned or otherwise encumbered or disposed of until (i) the Restricted Stock Units have vested as
provided in Paragraph 2 of this Agreement and (ii) shares of Stock have been issued to the Participant in accordance with the terms of the Plan and this Agreement. 

2.    Vesting of Restricted Stock Units. The restrictions and conditions of Paragraph 1 of this Agreement
shall lapse on the vesting date or dates specified in the following schedule so long as the Participant remains an employee of the Company or a Subsidiary on such vesting dates. If a series of vesting dates is specified, then the restrictions and
conditions in Paragraph 1 shall lapse only with respect to the number of Restricted Stock Units specified as vested on such date. 
  

			
	 Number of
Restricted Stock Units
Vested
	  	 Vesting Date

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

	
                
    
	  	
                
    

 The Administrator may at any time accelerate the vesting schedule specified in this Paragraph 2. 

3.    Termination of Employment. If the Participant’s employment with the Company and its Subsidiaries
terminates by reason of death, this Award and all vesting conditions set forth in Paragraph 2 above will accelerate and become vested upon the date of the Participant’s death. If the Participant’s employment with the Company and its
Subsidiaries terminates for any reason 

 
other than death prior to the satisfaction of the vesting conditions set forth in Paragraph 2 above, any Restricted Stock Units that have not vested as of such date shall automatically and
without notice terminate and be forfeited, and neither the Participant nor any of his or her successors, heirs, assigns, or personal representatives will thereafter have any further rights or interests in such unvested Restricted Stock Units. 

4.    Issuance of Shares of Stock. As soon as practicable following each vesting date (but in no event later than
two and one-half months after the end of the year in which the vesting date occurs), the Company shall issue to the Participant (or the Participant’s estate) the number of shares of Stock equal to the
aggregate number of Restricted Stock Units that have vested pursuant to Paragraph 2 of this Agreement on such date and the Participant shall thereafter have all the rights of a stockholder of the Company with respect to such shares. 

5.    Incorporation of Plan. Notwithstanding anything herein to the contrary, this Agreement shall be subject to
and governed by all the terms and conditions of the Plan, including the powers of the Administrator set forth in Section 2(b) of the Plan. Capitalized terms in this Agreement shall have the meaning specified in the Plan, unless a different
meaning is specified herein. 
 6.    Tax Withholding. The Participant shall, not later than the date as of which
the receipt of this Award becomes a taxable event for Federal income tax purposes, pay to the Company or make arrangements satisfactory to the Company for payment of any Federal, state, and local taxes required by law to be withheld on account of
such taxable event. The Company shall have the authority to cause the required tax withholding obligation to be satisfied, in whole or in part, by withholding from shares of Stock to be issued to the Participant a number of shares of Stock with an
aggregate Fair Market Value that would satisfy the withholding amount due. 
 7.    Section 409A of the Code.
This Agreement shall be interpreted in such a manner that all provisions relating to the settlement of the Award are exempt from the requirements of Section 409A of the Code as “short-term deferrals” as described in Section 409A
of the Code. 
 8.    No Obligation to Continue Employment. Neither the Company nor any Subsidiary is obligated
by or as a result of the Plan or this Agreement to continue the Participant in employment and neither the Plan nor this Agreement shall interfere in any way with the right of the Company or any Subsidiary to terminate the employment of the
Participant at any time. 
 9.    Integration. This Agreement constitutes the entire agreement between the
parties with respect to this Award and supersedes all prior agreements and discussions between the parties concerning such subject matter. 

10.    Data Privacy Consent. In order to administer the Plan and this Agreement and to implement or structure
future equity grants, the Company, its subsidiaries and affiliates and certain agents thereof (together, the “Relevant Companies”) may process any and all personal or professional data, including but not limited to Social Security
or other identification number, home address and telephone number, date of birth and other information that is necessary or desirable for the administration of the Plan and/or this Agreement (the “Relevant Information”). By entering
into this Agreement, the Participant (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information; (ii) waives any privacy 

  
 2 

 
rights the Participant may have with respect to the Relevant Information; (iii) authorizes the Relevant Companies to store and transmit such information in electronic form; and
(iv) authorizes the transfer of the Relevant Information to any jurisdiction in which the Relevant Companies consider appropriate. The Participant shall have access to, and the right to change, the Relevant Information. Relevant Information
will only be used in accordance with applicable law. 
 11.    Notices. Notices hereunder shall be mailed or
delivered to the Company at its principal place of business and shall be mailed or delivered to the Participant at the address on file with the Company or, in either case, at such other address as one party may subsequently furnish to the other
party in writing. 
  

									
		 		 	     CODIAK BIOSCIENCES, INC.	  	

									
					
		 		 	By:	  	  
	  	
		 		 		  	Title:	  	

							
	
	Electronic acceptance of this Agreement pursuant to the Company’s instructions or your signature below (including through an online acceptance process) shall constitute your acceptance of the terms and conditions in
this agreement.
				
	Dated:
                                         
           	 		  	  
	  	
		 		  	Participant’s Signature	  	
				
		 	            	  	Participant’s name and address:	  	
				
		 		  	  
	  	
				
		 		  	  
	  	
				
		 		  	  
	  	

  
 3

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