Document:

EX-10.10

 Exhibit 10.10 

EMPLOYMENT AGREEMENT 

This Employment Agreement (“Agreement”) is made between Unum Therapeutics Inc., a Delaware corporation (the “Company”),
and Christiana Stamoulis (the “Executive”) and is made effective as of the closing of the Company’s first underwritten public offering of its equity securities pursuant to an effective registration statement under the Securities Act
of 1933, as amended (the “Effective Date”). 
 In consideration of the mutual covenants and agreements herein contained and other
good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties agree as follows: 
 1.
Employment. 
 (a) Term. The term of this Agreement shall commence on the Effective Date and continue until the Date of
Termination (as defined herein) (such period shall hereinafter be referred to as the “Term”). No provision of this Agreement shall be construed as altering the “at will” nature of Executive’s employment, and the
Executive’s employment may be terminated at any time for any reason. 
 (b) Position and Duties. During the Term, the Executive
shall serve as the President and Chief Financial Officer of the Company, and shall have supervision and control over and responsibility for the day-to-day business and
affairs of the Company and shall have such other powers and duties as may from time to time be prescribed by the Chairman of the Board of Directors of the Company (the “Board”), the Chief Executive Officer of the Company (the
“CEO”) or other authorized executive, provided that such duties are consistent with the Executive’s position or other positions that he may hold from time to time. The Executive shall devote his full working time and efforts to the
business and affairs of the Company. Notwithstanding the foregoing, the Executive may serve on other boards of directors, with the approval of the CEO, or engage in religious, charitable or other community activities as long as such services and
activities are disclosed to the CEO and do not materially interfere with the Executive’s performance of his duties to the Company as provided in this Agreement. 

2. Compensation and Related Matters. 

(a) Base Salary. During the Term, the Executive’s initial annual base salary shall be $425,000. The Executive’s base salary
shall be redetermined annually by the Board or the Compensation Committee. The base salary in effect at any given time is referred to herein as “Base Salary.” The Base Salary shall be payable in a manner that is consistent with the
Company’s usual payroll practices for senior executives. 
 (b) Incentive Compensation. During the Term, the Executive shall be
eligible to receive cash incentive compensation as determined by the Board or the Compensation Committee from time to time. The Executive’s target annual incentive compensation shall be 35 percent of his Base Salary. To earn incentive
compensation, the Executive must be employed by the Company on the day such incentive compensation is paid. 

 (c) Expenses. The Executive shall be entitled to receive prompt reimbursement for all
reasonable expenses incurred by him during the Term in performing services hereunder, in accordance with the policies and procedures then in effect and established by the Company for its senior executive officers. 

(d) Other Benefits. During the Term, the Executive shall be eligible to participate in or receive benefits under the Company’s
employee benefit plans in effect from time to time, subject to the terms of such plans. 
 (e) Vacations. During the Term, the
Executive shall be subject to the Company’s vacation policy as in effect from time to time at the Company. The Executive shall also be entitled to all paid holidays given by the Company to its executives. 

3. Termination. During the Term, the Executive’s employment hereunder may be terminated without any breach of this Agreement under
the following circumstances: 
 (a) Death. The Executive’s employment hereunder shall terminate upon his death. 

(b) Disability. The Company may terminate the Executive’s employment if he is disabled and unable to perform the essential
functions of the Executive’s then existing position or positions under this Agreement with or without reasonable accommodation for a period of 180 days (which need not be consecutive) in any 12-month
period. If any question shall arise as to whether during any period the Executive is disabled so as to be unable to perform the essential functions of the Executive’s then existing position or positions with or without reasonable accommodation,
the Executive may, and at the request of the Company shall, submit to the Company a certification in reasonable detail by a physician selected by the Company to whom the Executive or the Executive’s guardian has no reasonable objection as to
whether the Executive is so disabled or how long such disability is expected to continue, and such certification shall for the purposes of this Agreement be conclusive of the issue. The Executive shall cooperate with any reasonable request of the
physician in connection with such certification. If such question shall arise and the Executive shall fail to submit such certification, the Company’s determination of such issue shall be binding on the Executive. Nothing in this
Section 3(b) shall be construed to waive the Executive’s rights, if any, under existing law including, without limitation, the Family and Medical Leave Act of 1993, 29 U.S.C. §2601 et seq. and the Americans with Disabilities
Act, 42 U.S.C. §12101 et seq. 
 (c) Termination by Company for Cause. The Company may terminate the Executive’s
employment hereunder for Cause. For purposes of this Agreement, “Cause” shall mean: (i) conduct by the Executive constituting a material act of misconduct in connection with the performance of his duties, including, without
limitation, misappropriation of funds or property of the Company or any of its subsidiaries or affiliates other than the occasional, customary and de minimis use of Company property for personal purposes; (ii) the commission by the Executive of
any felony or a misdemeanor involving moral turpitude, deceit, dishonesty or fraud, or any conduct by the Executive that would reasonably be expected to result in material injury or reputational harm to the Company or any of its subsidiaries and
affiliates if he were retained in his position; (iii) continued non-performance by the Executive of his duties hereunder 

  
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(other than by reason of the Executive’s physical or mental illness, incapacity or disability) which has continued for more than 30 days following written notice of such non-performance from the CEO; (iv) a breach by the Executive of any of the provisions contained in Section 7 of this Agreement; (v) a material violation by the Executive of the Company’s written
employment policies; or (vi) failure to cooperate with a bona fide internal investigation or an investigation by regulatory or law enforcement authorities, after being instructed by the Company to cooperate, or the willful destruction or
failure to preserve documents or other materials known to be relevant to such investigation or the inducement of others to fail to cooperate or to produce documents or other materials in connection with such investigation. 

(d) Termination Without Cause. The Company may terminate the Executive’s employment hereunder at any time without Cause. Any
termination by the Company of the Executive’s employment under this Agreement which does not constitute a termination for Cause under Section 3(c) and does not result from the death or disability of the Executive under Section 3(a) or
(b) shall be deemed a termination without Cause. 
 (e) Termination by the Executive. The Executive may terminate his employment
hereunder at any time for any reason, including but not limited to Good Reason. For purposes of this Agreement, “Good Reason” shall mean that the Executive has complied with the “Good Reason Process” (hereinafter defined)
following the occurrence of any of the following events: (i) a material diminution in the Executive’s responsibilities, authority or duties, including a material change in reporting relationship; (ii) a material diminution of more
than 10% in the Executive’s Base Salary except for across-the-board salary reductions based on the Company’s financial performance similarly affecting all or
substantially all senior management employees of the Company; (iii) a change in the geographic location at which the Executive provides services to the Company more than sixty (60) miles away from the current location; or (iv) the
material breach of this Agreement by the Company. “Good Reason Process” shall mean that (i) the Executive reasonably determines in good faith that a “Good Reason” condition has occurred; (ii) the Executive notifies the
Company in writing of the first occurrence of the Good Reason condition within 60 days of the first occurrence of such condition; (iii) the Executive cooperates in good faith with the Company’s efforts, for a period not less than 30 days
following such notice (the “Cure Period”), to remedy the condition; (iv) notwithstanding such efforts, the Good Reason condition continues to exist; and (v) the Executive terminates his employment within 60 days after the end of
the Cure Period. If the Company cures the Good Reason condition during the Cure Period, Good Reason shall be deemed not to have occurred. 

(f) Notice of Termination. Except for termination as specified in Section 3(a), any termination of the Executive’s employment
by the Company or any such termination by the Executive shall be communicated by written Notice of Termination to the other party hereto. For purposes of this Agreement, a “Notice of Termination” shall mean a notice which shall indicate
the specific termination provision in this Agreement relied upon. 
 (g) Date of Termination. “Date of Termination” shall
mean: (i) if the Executive’s employment is terminated by his death, the date of his death; (ii) if the Executive’s employment is terminated on account of disability under Section 3(b) or by the Company for Cause under
Section 3(c), the date on which Notice of Termination is given; (iii) if the Executive’s employment is terminated by the Company under Section 3(d), the date on which a 

  
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Notice of Termination is given; (iv) if the Executive’s employment is terminated by the Executive under Section 3(e) without Good Reason, 30 days after the date on which a Notice
of Termination is given, and (v) if the Executive’s employment is terminated by the Executive under Section 3(e) with Good Reason, the date on which a Notice of Termination is given after the end of the Cure Period. Notwithstanding
the foregoing, in the event that the Executive gives a Notice of Termination to the Company, the Company may unilaterally accelerate the Date of Termination and such acceleration shall not result in a termination by the Company for purposes of this
Agreement. 
 4. Compensation Upon Termination. 

(a) Termination Generally. If the Executive’s employment with the Company is terminated for any reason, the Company shall pay or
provide to the Executive (or to his authorized representative or estate) (i) any Base Salary earned through the Date of Termination, unpaid expense reimbursements (subject to, and in accordance with, Section 2(c) of this Agreement) and
unused vacation that accrued through the Date of Termination on or before the time required by law but in no event more than 30 days after the Executive’s Date of Termination; and (ii) any vested benefits the Executive may have under any
employee benefit plan of the Company through the Date of Termination, which vested benefits shall be paid and/or provided in accordance with the terms of such employee benefit plans (collectively, the “Accrued Benefit”). 

(b) Termination by the Company Without Cause or by the Executive with Good Reason. During the Term, if the Executive’s employment
is terminated by the Company without Cause as provided in Section 3(d), or the Executive terminates his employment for Good Reason as provided in Section 3(e), then the Company shall pay the Executive his Accrued Benefit. In addition,
subject to the Executive signing a separation agreement containing, among other provisions, a general release of claims in favor of the Company and related persons and entities, confidentiality, return of property and mutual non-disparagement, in a form and manner satisfactory to the Company (the “Separation Agreement and Release”) and the Separation Agreement and Release becoming irrevocable, all within 60 days after the Date
of Termination: 
 (i) the Company shall pay the Executive a lump sum in cash in an amount equal to 9 months of
the Executive’s current Base Salary; and 
 (ii) upon the Date of Termination, all stock options and other
stock-based awards held by the Executive in which the Executive would have vested if he had remained employed for an additional 9 months following the Date of Termination shall vest and become exercisable or nonforfeitable as of the Date of
Termination; and 
 (iii) if the Executive was participating in the Company’s group health plan immediately prior to the
Date of Termination and elects COBRA health continuation, then the Company shall pay to the Executive a monthly cash payment for 9 months or the Executive’s COBRA health continuation period, whichever ends earlier, in an amount equal to
the monthly employer contribution that the Company would have made to provide health insurance to the Executive if the Executive had remained employed by the Company; and 

  
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 (iv) The amounts payable under this Section 4(b) shall be paid or commence
to be paid within 60 days after the Date of Termination; provided, however, that if the 60-day period begins in one calendar year and ends in a second calendar year, such payments shall be paid or commence to
be paid in the second calendar year by the last day of such 60-day period; provided, further, that the initial payment shall include a catch-up payment to cover amounts
retroactive to the day immediately following the Date of Termination. Notwithstanding the foregoing, if the Executive breaches any of the provisions contained in Section 7 of this Agreement, all payments under this Section 4(b) shall
immediately cease. 
 5. Change in Control Payment. The provisions of this Section 5 set forth certain terms of an agreement
reached between the Executive and the Company regarding the Executive’s rights and obligations upon the occurrence of a Change in Control of the Company. These provisions are intended to assure and encourage in advance the Executive’s
continued attention and dedication to his assigned duties and his objectivity during the pendency and after the occurrence of any such event. These provisions shall apply in lieu of, and expressly supersede, the provisions of Section 4(b)
regarding severance pay and benefits upon a termination of employment, if such termination of employment occurs within 12 months after the occurrence of the first event constituting a Change in Control. These provisions shall terminate and be of no
further force or effect beginning 12 months after the occurrence of a Change in Control. 
 (a) Change in Control. During the Term, if
within 12 months after a Change in Control, the Executive’s employment is terminated by the Company without Cause as provided in Section 3(d) or the Executive terminates his employment for Good Reason as provided in Section 3(e),
then, subject to the signing of the Separation Agreement and Release by the Executive and the Separation Agreement and Release becoming irrevocable, all within 60 days after the Date of Termination, 

(i) the Company shall pay the Executive a lump sum in cash in an amount equal to the sum of (A) 12 months of the
Executive’s current Base Salary (or the Executive’s Base Salary in effect immediately prior to the Change in Control, if higher) plus (B) 100 percent of the Executive’s target bonus; and 

(ii) notwithstanding anything to the contrary in any applicable option agreement or stock-based award agreement, all stock
options and other stock-based awards held by the Executive shall immediately accelerate and become fully exercisable or nonforfeitable as of the Date of Termination; and 

(iii) if the Executive was participating in the Company’s group health plan immediately prior to the Date of Termination
and elects COBRA health continuation, then the Company shall pay to the Executive a monthly cash payment for 12 months or the Executive’s COBRA health continuation period, whichever ends earlier, in an amount equal to the monthly employer
contribution that the Company would have made to provide health insurance to the Executive if the Executive had remained employed by the Company; and 

  
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 (iv) The amounts payable under this Section 5(a) shall be paid or commence
to be paid within 60 days after the Date of Termination; provided, however, that if the 60-day period begins in one calendar year and ends in a second calendar year, such payments shall be paid or commence to
be paid in the second calendar year by the last day of such 60-day period; provided, further, that the initial payment shall include a catch-up payment to cover amounts
retroactive to the day immediately following the Date of Termination. Notwithstanding the foregoing, if the Executive breaches any of the provisions contained in Section 7 of this Agreement, all payments under this Section 5(a) shall
immediately cease. 
 (b) Additional Limitation. 

(i) Anything in this Agreement to the contrary notwithstanding, in the event that the amount of any compensation, payment or
distribution by the Company to or for the benefit of the Executive, whether paid or payable or distributed or distributable pursuant to the terms of this Agreement or otherwise, calculated in a manner consistent with Section 280G of the Code
and the applicable regulations thereunder (the “Aggregate Payments”), would be subject to the excise tax imposed by Section 4999 of the Code, then the Aggregate Payments shall be reduced to the extent necessary so that no portion of
the Aggregate Payments would be subject to the excise tax. In such event, the Aggregate Payments shall be reduced in the following order: (1) cash payments not subject to Section 409A of the Code; (2) cash payments subject to
Section 409A of the Code; (3) equity-based payments and acceleration; and (4) non-cash forms of benefits. To the extent any payment is to be made over time (e.g., in installments, etc.), then
the payments shall be reduced in reverse chronological order. 
 (ii) The determination of the reduction provided in
Section 5(b)(i) shall be made by a nationally recognized accounting firm selected by the Company (the “Accounting Firm”), which shall provide detailed supporting calculations both to the Company and the Executive within 15 business
days of the Date of Termination, if applicable, or at such earlier time as is reasonably requested by the Company or the Executive. Any determination by the Accounting Firm shall be binding upon the Company and the Executive. 

(c) Definitions. For purposes of this Section 5, the following terms shall have the following meanings: 

“Change in Control” shall mean any of the following: 

(i) any “person,” as such term is used in Sections 13(d) and 14(d) of the Securities Exchange Act of 1934, as amended
(the “Act”) (other than the Company, any of its subsidiaries, or any trustee, fiduciary or other person or entity holding securities under any employee benefit plan or trust of the Company or any of its subsidiaries), together with all
“affiliates” and “associates” (as such terms are defined in Rule 12b-2 under the Act) of such person, shall become the “beneficial owner” (as such term is defined in Rule 13d-3 under the Act), directly or indirectly, of securities of the Company representing 50 percent or more of the combined voting power of the Company’s then outstanding securities having the right to vote
in an election of the Board (“Voting Securities”) (in such case other than as a result of an acquisition of securities directly from the Company); or 

  
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 (ii) the date a majority of the members of the Board is replaced during any 12-month period by directors whose appointment or election is not endorsed by a majority of the members of the Board before the date of the appointment or election; or 

(iii) the consummation of (A) any consolidation or merger of the Company where the stockholders of the Company,
immediately prior to the consolidation or merger, would not, immediately after the consolidation or merger, beneficially own (as such term is defined in Rule 13d-3 under the Act), directly or indirectly,
shares representing in the aggregate more than 50 percent of the voting shares of the Company issuing cash or securities in the consolidation or merger (or of its ultimate parent corporation, if any), or (B) any sale or other transfer (in
one transaction or a series of transactions contemplated or arranged by any party as a single plan) of all or substantially all of the assets of the Company. 

Notwithstanding the foregoing, a “Change in Control” shall not be deemed to have occurred for purposes of the foregoing clause
(i) solely as the result of an acquisition of securities by the Company which, by reducing the number of shares of Voting Securities outstanding, increases the proportionate number of Voting Securities beneficially owned by any person to
50 percent or more of the combined voting power of all of the then outstanding Voting Securities; provided, however, that if any person referred to in this sentence shall thereafter become the beneficial owner of any additional shares of Voting
Securities (other than pursuant to a stock split, stock dividend, or similar transaction or as a result of an acquisition of securities directly from the Company) and immediately thereafter beneficially owns 50 percent or more of the combined
voting power of all of the then outstanding Voting Securities, then a “Change in Control” shall be deemed to have occurred for purposes of the foregoing clause (i). 

6. Section 409A. 
 (a)
Anything in this Agreement to the contrary notwithstanding, if at the time of the Executive’s separation from service within the meaning of Section 409A of the Code, the Company determines that the Executive is a “specified
employee” within the meaning of Section 409A(a)(2)(B)(i) of the Code, then to the extent any payment or benefit that the Executive becomes entitled to under this Agreement on account of the Executive’s separation from service would be
considered deferred compensation otherwise subject to the 20 percent additional tax imposed pursuant to Section 409A(a) of the Code as a result of the application of Section 409A(a)(2)(B)(i) of the Code, such payment shall not be
payable and such benefit shall not be provided until the date that is the earlier of (A) six months and one day after the Executive’s separation from service, or (B) the Executive’s death. If any such delayed cash payment is
otherwise payable on an installment basis, the first payment shall include a catch-up payment covering amounts that would otherwise have been paid during the six-month
period but for the application of this provision, and the balance of the installments shall be payable in accordance with their original schedule. 

  
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 (b) All in-kind benefits provided and expenses eligible
for reimbursement under this Agreement shall be provided by the Company or incurred by the Executive during the time periods set forth in this Agreement. All reimbursements shall be paid as soon as administratively practicable, but in no event shall
any reimbursement be paid after the last day of the taxable year following the taxable year in which the expense was incurred. The amount of in-kind benefits provided or reimbursable expenses incurred in one
taxable year shall not affect the in-kind benefits to be provided or the expenses eligible for reimbursement in any other taxable year (except for any lifetime or other aggregate limitation applicable to
medical expenses). Such right to reimbursement or in-kind benefits is not subject to liquidation or exchange for another benefit. 

(c) To the extent that any payment or benefit described in this Agreement constitutes
“non-qualified deferred compensation” under Section 409A of the Code, and to the extent that such payment or benefit is payable upon the Executive’s termination of employment, then such
payments or benefits shall be payable only upon the Executive’s “separation from service.” The determination of whether and when a separation from service has occurred shall be made in accordance with the presumptions set forth in
Treasury Regulation Section 1.409A-1(h). 
 (d) The parties intend that this Agreement will be
administered in accordance with Section 409A of the Code. To the extent that any provision of this Agreement is ambiguous as to its compliance with Section 409A of the Code, the provision shall be read in such a manner so that all payments
hereunder comply with Section 409A of the Code. Each payment pursuant to this Agreement is intended to constitute a separate payment for purposes of Treasury Regulation Section 1.409A-2(b)(2). The
parties agree that this Agreement may be amended, as reasonably requested by either party, and as may be necessary to fully comply with Section 409A of the Code and all related rules and regulations in order to preserve the payments and
benefits provided hereunder without additional cost to either party. 
 (e) The Company makes no representation or warranty and shall have no
liability to the Executive or any other person if any provisions of this Agreement are determined to constitute deferred compensation subject to Section 409A of the Code but do not satisfy an exemption from, or the conditions of, such Section.

 7. Confidential Information, Noncompetition and Cooperation. 

(a) Confidential Information. As used in this Agreement, “Confidential Information” means information belonging to the Company
which is of value to the Company in the course of conducting its business and the disclosure of which could result in a competitive or other disadvantage to the Company. Confidential Information includes, without limitation, financial information,
reports, and forecasts; inventions, improvements and other intellectual property; trade secrets; know-how; designs, processes or formulae; software; market or sales information or plans; customer lists; and
business plans, prospects and opportunities (such as possible acquisitions or dispositions of businesses or facilities) which have been discussed or considered by the management of the Company. Confidential Information includes information developed
by the Executive in the course of the Executive’s employment by the Company, as well as other information to which the Executive may have access in connection with the 

  
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Executive’s employment. Confidential Information also includes the confidential information of others with which the Company has a business relationship. Notwithstanding the foregoing,
Confidential Information does not include information in the public domain, unless due to breach of the Executive’s duties under Section 7(b). 

(b) Confidentiality. The Executive understands and agrees that the Executive’s employment creates a relationship of confidence and
trust between the Executive and the Company with respect to all Confidential Information. At all times, both during the Executive’s employment with the Company and after its termination, the Executive will keep in confidence and trust all such
Confidential Information, and will not use or disclose any such Confidential Information without the written consent of the Company, except as may be necessary in the ordinary course of performing the Executive’s duties to the Company. For
avoidance of doubt, nothing in this Agreement shall be interpreted or applied to prohibit the Executive from making any good faith report to any governmental agency or other governmental entity concerning any act or omission that the Executive
reasonably believes constitutes a possible violation of federal or state law or making other disclosures that are protected under the anti-retaliation or whistleblower provisions of applicable federal or state law or regulation. In addition, for the
avoidance of doubt, pursuant to the federal Defend Trade Secrets Act of 2016, the Executive shall not be held criminally or civilly liable under any federal or state trade secret law for the disclosure of a trade secret that (i) is made
(A) in confidence to a federal, state or local government official, either directly or indirectly, or to an attorney and (B) solely for the purpose of reporting or investigating a suspected violation of law; or (ii) is made in a
complaint or other document filed in a lawsuit or other proceeding, if such filing is made under seal. 
 (c) Documents, Records, etc.
All documents, records, data, apparatus, equipment and other physical property, whether or not pertaining to Confidential Information, which are furnished to the Executive by the Company or are produced by the Executive in connection with the
Executive’s employment will be and remain the sole property of the Company. The Executive will return to the Company all such materials and property as and when requested by the Company. In any event, the Executive will return all such
materials and property immediately upon termination of the Executive’s employment for any reason. The Executive will not retain with the Executive any such material or property or any copies thereof after such termination. 

(d) Noncompetition and Nonsolicitation. During the Executive’s employment with the Company and for twelve (12) months
thereafter, regardless of the reason for the termination, the Executive (i) will not, directly or indirectly, whether as owner, partner, shareholder, consultant, agent, employee, co-venturer or otherwise, engage, participate, assist or invest
in any Competing Business (as hereinafter defined); (ii) will refrain from directly or indirectly employing, attempting to employ, recruiting or otherwise soliciting, inducing or influencing any person to leave employment with the Company (other
than terminations of employment of subordinate employees undertaken in the course of the Executive’s employment with the Company); and (iii) will refrain from soliciting or encouraging any customer or supplier to terminate or otherwise
modify adversely its business relationship with the Company. The Executive understands that the restrictions set forth in this Section 7(d) are intended to protect the Company’s interest in its Confidential Information and established
employee, customer and supplier relationships and goodwill, and agrees that such restrictions are reasonable and 

  
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appropriate for this purpose. For purposes of this Agreement, the term “Competing Business” shall mean any person, entity or organization engaged in, or anticipated to become engaged
in, research on or the acquisition, development, production, distribution, marketing, or providing of a cellular immunotherapy for the treatment of cancer anywhere in the United States of America. Notwithstanding the foregoing, the Executive may own
up to one percent (1%) of the outstanding stock of a publicly held corporation which constitutes or is affiliated with a Competing Business. 

(e) Third-Party Agreements and Rights. The Executive hereby confirms that the Executive is not bound by the terms of any agreement with
any previous employer or other party which restricts in any way the Executive’s use or disclosure of information or the Executive’s engagement in any business. The Executive represents to the Company that the Executive’s execution of
this Agreement, the Executive’s employment with the Company and the performance of the Executive’s proposed duties for the Company will not violate any obligations the Executive may have to any such previous employer or other party. In the
Executive’s work for the Company, the Executive will not disclose or make use of any information in violation of any agreements with or rights of any such previous employer or other party, and the Executive will not bring to the premises of the
Company any copies or other tangible embodiments of non-public information belonging to or obtained from any such previous employment or other party. 

(f) Litigation and Regulatory Cooperation. During and after the Executive’s employment, the Executive shall cooperate fully with
the Company in the defense or prosecution of any claims or actions now in existence or which may be brought in the future against or on behalf of the Company which relate to events or occurrences that transpired while the Executive was employed by
the Company. The Executive’s full cooperation in connection with such claims or actions shall include, but not be limited to, being available to meet with counsel to prepare for discovery or trial and to act as a witness on behalf of the
Company at mutually convenient times. During and after the Executive’s employment, the Executive also shall cooperate fully with the Company in connection with any investigation or review of any federal, state or local regulatory authority as
any such investigation or review relates to events or occurrences that transpired while the Executive was employed by the Company. The Company shall reimburse the Executive for any reasonable out-of-pocket expenses incurred in connection with the Executive’s performance of obligations pursuant to this Section 7(f). 

(g) Injunction. The Executive agrees that it would be difficult to measure any damages caused to the Company which might result from any
breach by the Executive of the promises set forth in this Section 7, and that in any event money damages would be an inadequate remedy for any such breach. Accordingly, subject to Section 8 of this Agreement, the Executive agrees that if
the Executive breaches, or proposes to breach, any portion of this Agreement, the Company shall be entitled, in addition to all other remedies that it may have, to an injunction or other appropriate equitable relief to restrain any such breach
without showing or proving any actual damage to the Company. 

  
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 8. Arbitration of Disputes. Any controversy or claim arising out of or relating to this
Agreement or the breach thereof or otherwise arising out of the Executive’s employment or the termination of that employment (including, without limitation, any claims of unlawful employment discrimination whether based on age or otherwise)
shall, to the fullest extent permitted by law, be settled by arbitration in any forum and form agreed upon by the parties or, in the absence of such an agreement, under the auspices of the American Arbitration Association (“AAA”) in
Boston, Massachusetts in accordance with the Employment Dispute Resolution Rules of the AAA, including, but not limited to, the rules and procedures applicable to the selection of arbitrators. In the event that any person or entity other than the
Executive or the Company may be a party with regard to any such controversy or claim, such controversy or claim shall be submitted to arbitration subject to such other person or entity’s agreement. Judgment upon the award rendered by the
arbitrator may be entered in any court having jurisdiction thereof. This Section 8 shall be specifically enforceable. Notwithstanding the foregoing, this Section 8 shall not preclude either party from pursuing a court action for the sole
purpose of obtaining a temporary restraining order or a preliminary injunction in circumstances in which such relief is appropriate; provided that any other relief shall be pursued through an arbitration proceeding pursuant to this Section 8.

 9. Consent to Jurisdiction. To the extent that any court action is permitted consistent with or to enforce Section 8 of this
Agreement, the parties hereby consent to the jurisdiction of the Superior Court of the Commonwealth of Massachusetts and the United States District Court for the District of Massachusetts. Accordingly, with respect to any such court action, the
Executive (a) submits to the personal jurisdiction of such courts; (b) consents to service of process; and (c) waives any other requirement (whether imposed by statute, rule of court, or otherwise) with respect to personal
jurisdiction or service of process. 
 10. Integration. This Agreement constitutes the entire agreement between the parties with
respect to the subject matter hereof and supersedes all prior agreements between the parties concerning such subject matter. 
 11.
Withholding. All payments made by the Company to the Executive under this Agreement shall be net of any tax or other amounts required to be withheld by the Company under applicable law. 

12. Successor to the Executive. This Agreement shall inure to the benefit of and be enforceable by the Executive’s personal
representatives, executors, administrators, heirs, distributees, devisees and legatees. In the event of the Executive’s death after his termination of employment but prior to the completion by the Company of all payments due him under this
Agreement, the Company shall continue such payments to the Executive’s beneficiary designated in writing to the Company prior to his death (or to his estate, if the Executive fails to make such designation). 

13. Enforceability. If any portion or provision of this Agreement (including, without limitation, any portion or provision of any
section of this Agreement) shall to any extent be declared illegal or unenforceable by a court of competent jurisdiction, then the remainder of this Agreement, or the application of such portion or provision in circumstances other than those as to
which it is so declared illegal or unenforceable, shall not be affected thereby, and each portion and provision of this Agreement shall be valid and enforceable to the fullest extent permitted by law. 

  
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 14. Survival. The provisions of this Agreement shall survive the termination of this
Agreement and/or the termination of the Executive’s employment to the extent necessary to effectuate the terms contained herein. 
 15.
Waiver. No waiver of any provision hereof shall be effective unless made in writing and signed by the waiving party. The failure of any party to require the performance of any term or obligation of this Agreement, or the waiver by any party
of any breach of this Agreement, shall not prevent any subsequent enforcement of such term or obligation or be deemed a waiver of any subsequent breach. 

16. Notices. Any notices, requests, demands and other communications provided for by this Agreement shall be sufficient if in writing
and delivered in person or sent by a nationally recognized overnight courier service or by registered or certified mail, postage prepaid, return receipt requested, to the Executive at the last address the Executive has filed in writing with the
Company or, in the case of the Company, at its main offices, attention of the Board. 
 17. Amendment. This Agreement may be amended
or modified only by a written instrument signed by the Executive and by a duly authorized representative of the Company. 
 18. Governing
Law. This is a Massachusetts contract and shall be construed under and be governed in all respects by the laws of the Commonwealth of Massachusetts, without giving effect to the conflict of laws principles of such Commonwealth. With respect to
any disputes concerning federal law, such disputes shall be determined in accordance with the law as it would be interpreted and applied by the United States Court of Appeals for the First Circuit. 

19. Counterparts. This Agreement may be executed in any number of counterparts, each of which when so executed and delivered shall be
taken to be an original; but such counterparts shall together constitute one and the same document. 
 20. Successor to Company. The
Company shall require any successor (whether direct or indirect, by purchase, merger, consolidation or otherwise) to all or substantially all of the business or assets of the Company expressly to assume and agree to perform this Agreement to the
same extent that the Company would be required to perform it if no succession had taken place. Failure of the Company to obtain an assumption of this Agreement at or prior to the effectiveness of any succession shall be a material breach of this
Agreement. 
 21. Gender Neutral. Wherever used herein, a pronoun in the masculine gender shall be considered as including the
feminine gender unless the context clearly indicates otherwise. 

  
 12 

 IN WITNESS WHEREOF, the parties have executed this Agreement effective on the date and year first
above written. 
  

			
	UNUM THERAPEUTICS INC.

  

			
	By:	 	 /s/ Charles Wilson

	Its:	 	 Chief Executive Officer

			
	
	 EXECUTIVE
  

	
	 /s/ Christiana Stamoulis

	Christiana Stamoulis
	President and Chief Financial Officer

  
 13EX-10.11

 Exhibit 10.11 

UNUM THERAPEUTICS INC. 

2018 STOCK OPTION AND INCENTIVE PLAN 

SECTION 1. GENERAL PURPOSE OF THE PLAN; DEFINITIONS 

The name of the plan is the Unum Therapeutics Inc. 2018 Stock Option and Incentive Plan (the “Plan”). The purpose of the Plan is to
encourage and enable the officers, employees, Non-Employee Directors and Consultants of Unum Therapeutics Inc. (the “Company”) and its Subsidiaries upon whose judgment, initiative and efforts the
Company largely depends for the successful conduct of its businesses to acquire a proprietary interest in the Company. It is anticipated that providing such persons with a direct stake in the Company’s welfare will assure a closer
identification of their interests with those of the Company and its stockholders, thereby stimulating their efforts on the Company’s behalf and strengthening their desire to remain with the Company. 

The following terms shall be defined as set forth 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. 

“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 Certificate” means a written or electronic document setting forth the terms and provisions
applicable to an Award granted under the Plan. Each Award Certificate 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. 

“Code” means the Internal Revenue Code of 1986, as amended, and any successor Code, and related rules,
regulations and interpretations. 
 “Consultant” means any natural person that provides bona fide services to the Company,
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. 

 “Dividend Equivalent Right” means an Award entitling the grantee 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 grantee. 

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

“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 admitted to quotation on the National Association of Securities Dealers Automated Quotation System, Nasdaq Global Market, The New York Stock Exchange or another national securities exchange,
the determination shall be made by reference to the Stock’s closing price 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; 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. 

“Initial Public Offering” means the first underwritten, firm commitment public offering pursuant to an effective registration
statement under the Act covering the offer and sale by the Company of its equity securities, or such other event as a result of or following which the Stock shall be publicly held. 

“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. 
 “Registration Date” means
the date upon which the registration statement on Form S-1 that is filed by the Company with respect to the 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. 

  
 2 

 “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. 
 “Stock” means the Common Stock, par value $0.001 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 Certificate) 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. 

“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. 

SECTION 2. ADMINISTRATION OF PLAN; ADMINISTRATOR AUTHORITY TO SELECT GRANTEES 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: 

  
 3 

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

(ii) to determine the time or times of grant, and the extent, if any, 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, or any combination of the
foregoing, granted to any one or more grantees; 
 (iii) to determine the number of shares of Stock to be covered by any Award; 

(iv) to determine and 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 forms of Award Certificates; 

(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; and 

(vii) 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 related written instruments); 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
Administrator shall be binding on all persons, including the Company and Plan grantees. 
 (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 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. Any such delegation by the Administrator shall include a limitation
as to the amount of Stock underlying Awards that may be granted during the period of the delegation and shall contain guidelines as to the determination of the exercise price and the vesting criteria. 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 Certificate. Awards under the Plan shall be evidenced by Award Certificates that set forth 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. 

  
 4 

 (e) Indemnification. Neither the Board nor the Administrator, 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 Administrator (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 articles 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. 
 (f) 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 its Subsidiaries operate or have employees or other individuals eligible for Awards, the Administrator, in its sole discretion, shall have the power and authority to: (i) determine which Subsidiaries
shall be covered by the Plan; (ii) determine which individuals 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 Administrator determines such actions to be necessary or advisable (and such subplans and/or modifications
shall be attached to this Plan as appendices); provided, however, that no such subplans and/or modifications shall increase the share limitations contained in Section 3(a) hereof; and (v) take any action, before or after an Award is
made, that the Administrator determines to be necessary or advisable to obtain approval or comply with any local governmental regulatory exemptions or approvals. 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) Stock Issuable. The maximum number of shares of Stock reserved and available for issuance under the Plan shall be 2,547,5581 shares, plus the number of shares of Stock which were available for grant, as of the date of approval of the Plan by the Company’s stockholders under the Company’s 2015 Stock Incentive
Plan, (the “Initial Limit”), subject to adjustment as provided in Section 3(d), plus on January 1, 2019 and each January 1 thereafter, the number of shares of Stock reserved and available for issuance
under the Plan shall be cumulatively increased by 4 percent of the number of shares of Stock issued and outstanding on the immediately preceding December 31 or such lesser number determined by the Administrator (the “Annual
Increase”). In addition, the shares of Stock underlying any awards under the Plan and under the Company’s 2015 Stock Incentive 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.
Subject to such overall limitation, the maximum aggregate number of 
  

	1 	Reflects the 1 for every 1.5701314513884 shares reverse stock split approved by the Board of Directors on March 8, 2018. 

  
 5 

 shares of Stock that may be issued in the form of Incentive Stock Options shall not exceed the Initial Limit
cumulatively increased on January 1, 2019 and on each January 1 thereafter by the lesser of the Annual Increase for such year or 800,0002 shares of Stock, subject in all cases to
adjustment as provided in Section 3(d). 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. The shares
available for issuance under the Plan may be authorized but unissued shares of Stock or shares of Stock reacquired by the Company. 
 (b)
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 $1,000,000. 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. 
 (c)
Reserved. 
 (d) Changes in Stock. Subject to Section 3(e) 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 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 shares 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, or, if, as a result of any merger or consolidation, sale of all or substantially all of the assets of the Company, the outstanding shares of Stock are converted into or exchanged for securities of the Company or any
successor entity (or a parent or subsidiary thereof), the Administrator shall make an appropriate or proportionate adjustment in (i) the maximum number of shares reserved for issuance under the Plan, including the maximum number of shares that
may be issued in the form of Incentive Stock Options, (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
Restricted Stock Award, and (iv) the exercise price for each share subject to any then outstanding Stock Options and Stock Appreciation Rights under the Plan, without changing the aggregate exercise price (i.e., the exercise price multiplied by
the number of Stock Options and Stock Appreciation Rights) as to which such Stock Options and Stock Appreciation Rights remain exercisable. The Administrator shall also make equitable or proportionate adjustments in the number of shares subject to
outstanding Awards and the exercise price and the terms of outstanding Awards to take into consideration cash dividends paid other than in the ordinary course or any other extraordinary corporate event. The adjustment by the Administrator shall be
final, binding and conclusive. No fractional shares of Stock shall be issued under the Plan resulting from any such adjustment, but the Administrator in its discretion may make a cash payment in lieu of fractional shares. 

 
  

	2 	Reflects the 1 for every 1.5701314513884 shares reverse stock split approved by the Board of Directors on March 8, 2018. 

  
 6 

 (e) Mergers and Other Transactions. In the case of and subject to the consummation of a
Sale Event, the parties thereto may cause the assumption or continuation of Awards theretofore granted by the successor entity, 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 and, if appropriate, the per share exercise prices, as such parties shall agree. To the extent the parties to such Sale Event do not provide for the assumption, continuation or substitution of Awards, upon the
effective time of the Sale Event, the Plan and all outstanding Awards granted hereunder shall terminate. In such case, except as may be otherwise provided in the relevant Award Certificate, all Options and Stock Appreciation Rights that are not
exercisable immediately prior to the effective time of the Sale Event shall become fully 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 Certificate. In the event of such termination, (i) the Company shall have the option (in its sole discretion) to make or provide for a payment, in cash or in kind,
to the grantees holding Options and Stock Appreciation Rights, in exchange for the cancellation thereof, in 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 exercisable 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 less than the Sale Price, such Option or Stock Appreciation Right shall be cancelled for no consideration); or (ii) each grantee shall be permitted, 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) held by such grantee. The Company shall also have the option (in
its sole discretion) to make or provide for a payment, in cash or in kind, to the grantees holding other Awards in an amount equal to the Sale Price multiplied by the number of vested shares of Stock under such Awards. 

SECTION 4. ELIGIBILITY 
 Grantees under
the Plan will be such full or part-time officers and other employees, Non-Employee Directors and Consultants of the Company and its Subsidiaries 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 the Administrator may from time to time approve. 
 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. 

  
 7 

 Stock Options granted pursuant to this Section 5 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 Administrator shall deem desirable. If the Administrator so determines, Stock Options may be granted in lieu of cash compensation
at the optionee’s election, subject to such terms and conditions as the Administrator may establish. 
 (b) Exercise Price. The
exercise price per share for the Stock covered by a Stock Option granted pursuant to this Section 5 shall be determined by the Administrator at the time of grant but shall not be less than 100 percent of the Fair Market Value on the date
of grant. In the case of an Incentive Stock Option that is granted to a Ten Percent Owner, the option 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. 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. 
 (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 Certificate: 
 (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 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 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. 

  
 8 

 Payment instruments will be received subject to collection. The transfer to the optionee 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 optionee (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 Certificate or applicable provisions of laws (including the satisfaction of any withholding taxes that the
Company is obligated to withhold with respect to the optionee). In the event an optionee 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 optionee
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 optionee 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. A Stock Appreciation Right
is an Award entitling the recipient to receive shares of Stock (or cash, to the extent explicitly provided for in the applicable Award Certificate) having a value equal to the excess of the Fair Market Value of a share of 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. 

(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 such terms and conditions as shall
be determined on the date of grant by the Administrator. The term of a Stock Appreciation Right may not exceed ten years. 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 grantees. 

  
 9 

 SECTION 7. RESTRICTED STOCK AWARDS 

(a) Nature of Restricted Stock Awards. The Administrator may grant Restricted Stock Awards under the Plan. A Restricted Stock Award is
any Award of Restricted Shares subject to such restrictions and conditions as the Administrator may determine 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. 
 (b) Rights as a Stockholder. Upon the grant of
the Restricted Stock Award and payment of any applicable purchase price, a grantee 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 grantee until and to the extent the performance goals are
met with respect to the Restricted Stock Award. Unless the Administrator shall otherwise determine, (i) 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 (ii) certificated Restricted Shares shall remain in the possession of the Company until such Restricted Shares are vested as
provided in Section 7(d) below, and the grantee 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 Certificate. Except as may otherwise be provided by the Administrator either in the Award Certificate or, subject to Section 16 below, in writing after the Award is issued, if a
grantee’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 requirement of
notice to such grantee from or other action by or on behalf of, the Company be deemed to have been reacquired by the Company at its original purchase price (if any) from such grantee or such grantee’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 grantee or rights of the grantee as a stockholder. Following such deemed reacquisition of Restricted Shares
that are represented by physical certificates, a grantee 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.” 

  
 10 

 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 Certificate) 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 grantees. 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. 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. 
 (b) Election to
Receive Restricted Stock Units in Lieu of Compensation. The Administrator may, in its sole discretion, permit a grantee to elect to receive a portion of future cash compensation otherwise due to such grantee 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 grantee 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 grantee 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 Certificate. 

(c) Rights as a Stockholder. A grantee shall have the rights as a stockholder only as to shares of Stock acquired by the grantee upon
settlement of Restricted Stock Units; provided, however, that the grantee may be credited with Dividend Equivalent Rights with respect to the stock units underlying his Restricted Stock Units, subject to such terms and conditions as the
Administrator may determine. 
 (d) Termination. Except as may otherwise be provided by the Administrator either in the Award
Certificate or, subject to Section 16 below, in writing after the Award is issued, a grantee’s right in all Restricted Stock Units that have not vested shall automatically terminate upon the grantee’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 grantee 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 grantee. 

  
 11 

 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 grantee 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 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 grantee 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 grantee. A Dividend Equivalent Right may be granted hereunder to any grantee 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 Certificate. 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 Certificate or, subject to Section 16
below, in writing after the Award is issued, a grantee’s rights in all Dividend Equivalent Rights shall automatically terminate upon the grantee’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 grantee’s lifetime, his or her Awards shall be
exercisable only by the grantee, or by the grantee’s legal representative or guardian in the event of the grantee’s incapacity. No Awards shall be sold, assigned, transferred or otherwise encumbered or disposed of by a grantee 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. 

  
 12 

 (b) Administrator Action. Notwithstanding Section 12(a), the Administrator, in its
discretion, may provide either in the Award Certificate regarding a given Award or by subsequent written approval that the grantee (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 grantee for value. 
 (c)
Family Member. For purposes of Section 12(b), “family member” shall mean a grantee’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 grantee’s household (other than
a tenant of the grantee), a trust in which these persons (or the grantee) have more than 50 percent of the beneficial interest, a foundation in which these persons (or the grantee) control the management of assets, and any other entity in which
these persons (or the grantee) own more than 50 percent of the voting interests. 
 (d) Designation of Beneficiary. To the extent
permitted by the Company, each grantee 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 grantee’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 grantee, or if the designated beneficiaries have
predeceased the grantee, the beneficiary shall be the grantee’s estate. 
 SECTION 13. 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 Stock or other amounts
received thereunder first becomes includable in the gross income of the grantee for Federal 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
grantee. The Company’s obligation to deliver evidence of book entry (or stock certificates) to any grantee is subject to and conditioned on tax withholding obligations being satisfied by the grantee. 

  
 13 

 (b) Payment in Stock. Subject to approval by the Administrator, a grantee may elect to
have the Company’s minimum required tax withholding obligation satisfied, in whole or in part, by authorizing the Company to withhold 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. The Administrator may also require Awards to be subject to mandatory share withholding up to the required withholding amount. 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 required tax withholding obligation may also 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. 
 SECTION
14. 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 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 grantee 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 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 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 EMPLOYMENT, TRANSFER, LEAVE OF ABSENCE, ETC. 

(a) Termination of Employment. If the grantee’s employer ceases to be a Subsidiary, the grantee shall be deemed to have terminated
employment for purposes of the Plan. 
 (b) For purposes of the Plan, the following events shall not be deemed a termination of employment:

 (i) a transfer to the employment of the Company from a Subsidiary or from the Company to a Subsidiary, or from one Subsidiary 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. 

  
 14 

 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 adversely affect rights under any outstanding Award without the holder’s consent. Except as provided in Section 3(d) or 3(e), without prior
stockholder approval, in no event may the Administrator exercise its discretion to reduce the exercise price of outstanding Stock Options or Stock Appreciation Rights or effect repricing through cancellation and
re-grants or cancellation of Stock Options or Stock Appreciation Rights in exchange for cash or other Awards. 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
the Company stockholders entitled to vote at a meeting of stockholders. Nothing in this Section 16 shall limit the Administrator’s authority to take any action permitted pursuant to Section 3(d) or 3(e). 

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 grantee, a grantee 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 grantees 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 grantee, at the grantee’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 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). 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 

  
 15 

 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. 
 (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 grantee 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 the Company’s clawback policy, as in effect from time to time. 

SECTION 19. EFFECTIVE DATE OF PLAN 
 This
Plan shall become effective upon the date immediately preceding the Registration Date following stockholder approval of the Plan 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 laws of the State of
Delaware, applied without regard to conflict of law principles. 
 DATE APPROVED BY BOARD OF DIRECTORS: February 9, 2018 

DATE APPROVED BY STOCKHOLDERS: March 15, 2018  

  
 16 

 RESTRICTED STOCK UNIT AWARD AGREEMENT 

FOR NON-EMPLOYEE DIRECTORS 

UNDER THE UNUM THERAPEUTICS INC. 

2018 STOCK OPTION AND INCENTIVE PLAN 
  

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

 Pursuant to the Unum Therapeutics Inc. 2018 Stock Option and Incentive Plan as amended through the date hereof
(the “Plan”), Unum Therapeutics Inc. (the “Company”) hereby grants an award of the number of Restricted Stock Units listed above (an “Award”) to the Grantee named above. Each Restricted Stock Unit shall relate to one
share of Common Stock, par value $0.001 per share (the “Stock”) of the Company. 
 1. Restrictions on Transfer of Award.
This Award may not be sold, transferred, pledged, assigned or otherwise encumbered or disposed of by the Grantee, 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 Grantee 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 Grantee remains in service as a member of the Board 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. 
  

			
	 Incremental 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 Service. If the Grantee’s service with the Company and its Subsidiaries terminates for any reason (including
death or disability) 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 Grantee 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 Grantee 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 Grantee 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 Grantee 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 Grantee (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information;
(ii) waives any privacy rights the Grantee 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 Grantee shall have access to, and the right to change, the Relevant Information. Relevant Information will only be used in accordance with applicable
law. 

  
 2 

 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 Grantee 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. 

 

			
	UNUM THERAPEUTICS INC.

 
			
		
	By:	 	  

		 	Title:

 The foregoing Agreement is hereby accepted and the terms and conditions thereof hereby agreed to by the undersigned.
Electronic acceptance of this Agreement pursuant to the Company’s instructions to the Grantee (including through an online acceptance process) is acceptable. 
  

									
	Dated:
                                         
                               	 		 		 	  

		 		 		 	Grantee’s Signature
				
		 		 		 	Grantee’s name and address:
				
		 		 		 	  

				
		 		 		 	  

				
		 		 		 	  

  
 3 

 RESTRICTED STOCK AWARD AGREEMENT 

UNDER THE UNUM THERAPEUTICS INC. 

2018 STOCK OPTION AND INCENTIVE PLAN 
  

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

 Pursuant to the Unum Therapeutics Inc. 2018 Stock Option and Incentive Plan (the “Plan”) as amended
through the date hereof, Unum Therapeutics Inc. (the “Company”) hereby grants a Restricted Stock Award (an “Award”) to the Grantee named above. Upon acceptance of this Award, the Grantee shall receive the number of shares of
Common Stock, par value $0.001 per share (the “Stock”) of the Company specified above, subject to the restrictions and conditions set forth herein and in the Plan. The Company acknowledges the receipt from the Grantee of consideration with
respect to the par value of the Stock in the form of cash, past or future services rendered to the Company by the Grantee or such other form of consideration as is acceptable to the Administrator. 

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 Grantee’s name shall be entered as the stockholder of record on the books of the Company. Thereupon, the Grantee 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 Grantee 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 Grantee prior to vesting. 

(c) If the Grantee’s employment with the Company and its Subsidiaries is voluntarily or involuntarily terminated for any reason (including
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 Grantee 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. 
  

			
	 Incremental 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 Grantee. 

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 Grantee, 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 Grantee 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 Administrator 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 minimum 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 minimum
withholding amount due. 
 8. Election Under Section 83(b). The Grantee and the Company hereby agree that the
Grantee 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 Internal Revenue Code. In the event the Grantee makes such an election, he or she
agrees to provide a copy of the election to the Company. The Grantee 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 Grantee 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
Grantee 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 Grantee (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information;
(ii) waives any privacy rights the Grantee 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 Grantee 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 Grantee 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. 

 

			
	UNUM THERAPEUTICS INC.

 
			
		
	By:	 	  

		 	Title:

 The foregoing Agreement is hereby accepted and the terms and conditions thereof hereby agreed to by the undersigned.
Electronic acceptance of this Agreement pursuant to the Company’s instructions to the Grantee (including through an online acceptance process) is acceptable. 
  

									
	Dated:
                                         
                                   	 		 		 	  

		 		 		 	Grantee’s Signature
				
		 		 		 	Grantee’s name and address:
				
		 		 		 	  

				
		 		 		 	  

				
		 		 		 	  

  
 4 

 RESTRICTED STOCK UNIT AWARD AGREEMENT 

FOR COMPANY EMPLOYEES 

UNDER THE UNUM THERAPEUTICS INC. 

2018 STOCK OPTION AND INCENTIVE PLAN 
  

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

 Pursuant to the Unum Therapeutics Inc. 2018 Stock Option and Incentive Plan as amended through the date hereof
(the “Plan”), Unum Therapeutics Inc. (the “Company”) hereby grants an award of the number of Restricted Stock Units listed above (an “Award”) to the Grantee named above. Each Restricted Stock Unit shall relate to one
share of Common Stock, par value $0.001 per share (the “Stock”) of the Company. 
 1. Restrictions on Transfer of Award.
This Award may not be sold, transferred, pledged, assigned or otherwise encumbered or disposed of by the Grantee, 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 Grantee 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 Grantee 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 1 shall
lapse only with respect to the number of Restricted Stock Units specified as vested on such date. 
  

			
	 Incremental 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 Grantee’s employment with the Company and its Subsidiaries terminates for any reason
(including death or disability) 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 Grantee 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 Grantee 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 Grantee 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 Grantee 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 Administrator 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 minimum tax withholding obligation to be satisfied, in whole or in part, by withholding from shares of Stock to be issued to the Grantee 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 Grantee 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 Grantee 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 Grantee (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information; (ii) waives any privacy rights the
Grantee 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 Grantee shall have access to, and the right to change, the Relevant Information. Relevant Information will only be used in accordance with applicable law. 

  
 2 

 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 Grantee 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. 

 

			
	UNUM THERAPEUTICS INC.
		
	By:	 	  

		 	Title:

 The foregoing Agreement is hereby accepted and the terms and conditions thereof hereby agreed to by the undersigned.
Electronic acceptance of this Agreement pursuant to the Company’s instructions to the Grantee (including through an online acceptance process) is acceptable. 
  

							
	Dated:	 	  
	 		 	  

		 		 		 	Grantee’s Signature
				
		 		 		 	Grantee’s name and address:
				
		 		 		 	  

				
		 		 		 	  

				
		 		 		 	  

  
 3 

 NON-QUALIFIED STOCK OPTION AGREEMENT 

FOR NON-EMPLOYEE DIRECTORS 

UNDER THE UNUM THERAPEUTICS INC. 

2018 STOCK OPTION AND INCENTIVE PLAN 
  

					
	Name of Optionee:	 	                                    
                                         
                                       
			
	No. of Option Shares:	 	  
	 	
			
	Option Exercise Price per Share:     $	 	  
	 	
			
	Grant Date:	 	  
	 	
			
	Expiration Date:	 	  
	 	

 Pursuant to the Unum Therapeutics Inc. 2018 Stock Option and Incentive Plan as amended through the date hereof
(the “Plan”), Unum Therapeutics Inc. (the “Company”) hereby grants to the Optionee named above, who is a Director of the Company but is not an employee of the Company, an option (the “Stock Option”) to purchase on or
prior to the Expiration Date specified above all or part of the number of shares of Common Stock, par value $0.001 per share (the “Stock”), of the Company specified above at the Option Exercise Price per Share specified above subject to
the terms and conditions set forth herein and in the Plan. This Stock Option is not intended to be an “incentive stock option” under Section 422 of the Internal Revenue Code of 1986, as amended. 

1. Exercisability Schedule. No portion of this Stock Option may be exercised until such portion shall have become exercisable. Except as
set forth below, and subject to the discretion of the Administrator (as defined in Section 2 of the Plan) to accelerate the exercisability schedule hereunder, this Stock Option shall be exercisable with respect to the following number of Option
Shares on the dates indicated so long as the Optionee remains in service as a member of the Board on such dates: 
  

			
	 Incremental Number of

Option Shares Exercisable
	  	Exercisability Date
		
	
                
         (___%)
	  	                            
	
                
         (___%)
	  	                            
	
                
         (___%)
	  	                            
	
                
         (___%)
	  	                            
	
                
         (___%)
	  	                            

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

 2. Manner of Exercise. 

(a) The Optionee may exercise this Stock Option only in the following manner: from time to time on or prior to the Expiration Date of this
Stock Option, the Optionee may give written notice to the Administrator of his or her election to purchase some or all of the Option Shares purchasable at the time of such notice. This notice shall specify the number of Option Shares to be
purchased. 
 Payment of the purchase price for the Option Shares may be made by one or more of the following methods: (i) in cash, by
certified or bank check or other instrument acceptable to the Administrator; (ii) through the delivery (or attestation to the ownership) of shares of Stock 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 any restrictions under any Company plan and that otherwise satisfy any holding periods as may be required by the Administrator; (iii) 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 to pay the option purchase price, provided that in the event the Optionee chooses to
pay the option 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 Administrator shall prescribe as a condition of such payment
procedure; (iv) 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; or (v) a combination of (i), (ii), (iii) and (iv) above. Payment instruments will be received subject to collection. 

The transfer to the Optionee on the records of the Company or of the transfer agent of the Option Shares will be contingent upon (i) the
Company’s receipt from the Optionee 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 Optionee 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 Optionee 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 Optionee on the records of the Company or of the transfer agent upon compliance to the satisfaction of the Administrator with all requirements under applicable laws or
regulations in connection with such transfer and with the requirements hereof and of the Plan. The determination of the Administrator as to such compliance shall be final and binding on the Optionee. The Optionee 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 exercised pursuant to the terms hereof, the Company or the transfer agent shall have
transferred the shares to the Optionee, and the Optionee’s name shall have been entered as the stockholder of record on the books of the Company. Thereupon, the Optionee shall have full voting, dividend and other ownership rights with respect
to such shares of Stock. 

  
 2 

 (c) 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. 

(d) Notwithstanding any other provision hereof or of the Plan, no portion of this Stock Option shall be exercisable after the Expiration Date
hereof. 
 3. Termination as Director. If the Optionee ceases to be a Director of the Company, 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 Optionee’s service
as a Director terminates by reason of the Optionee’s 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 Optionee’s legal representative or
legatee for a period of 12 months from the date of death or until the Expiration Date, if earlier. Any portion of this Stock Option that is not exercisable on the date of death shall terminate immediately and be of no further force or effect. 

(b) Other Termination. If the Optionee ceases to be a Director for any reason other than the Optionee’s death, any portion of this
Stock Option outstanding on such date may be exercised, to the extent exercisable on the date the Optionee ceased to be a Director, for a period of six months from the date the Optionee ceased to be a Director or until the Expiration Date, if
earlier. Any portion of this Stock Option that is not exercisable on the date the Optionee ceases to be a Director shall terminate immediately and be of no further force or effect. 

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 Optionee, 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 Optionee’s lifetime, only by the Optionee, and thereafter, only by the
Optionee’s legal representative or legatee. 
 6. No Obligation to Continue as a Director. Neither the Plan nor this Stock Option
confers upon the Optionee any rights with respect to continuance as a Director. 
 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. 

  
 3 

 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 Optionee (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information; (ii) waives any privacy rights the Optionee 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 Optionee shall have access to, and the right to change, the Relevant Information. Relevant Information will only be used in accordance with applicable law. 

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 Optionee 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. 

 

			
	UNUM THERAPEUTICS INC.
		
	By:	 	 
		 	Title:

 The foregoing Agreement is hereby accepted and the terms and conditions thereof hereby agreed to by the undersigned.
Electronic acceptance of this Agreement pursuant to the Company’s instructions to the Optionee (including through an online acceptance process) is acceptable. 
  

							
	Dated:	 	  
	 		 	  

		 		 		 	Optionee’s Signature
				
		 		 		 	Optionee’s name and address:
				
		 		 		 	  

				
		 		 		 	  

				
		 		 		 	  

  
 4 

 INCENTIVE STOCK OPTION AGREEMENT 

UNDER THE UNUM THERAPEUTICS INC. 

2018 STOCK OPTION AND INCENTIVE PLAN 
  

									
	Name of Optionee:	  		  	  

					
	No. of Option Shares:	  		  	  
	  		  	
					
	Option Exercise Price per Share:	  	$	  	  
	  		  	
					
	Grant Date:	  		  	  
	  		  	
					
	Expiration Date:	  		  	  
	  		  	

 Pursuant to the Unum Therapeutics Inc. 2018 Stock Option and Incentive Plan as amended through the date hereof
(the “Plan”), Unum Therapeutics Inc. (the “Company”) hereby grants to the Optionee named above an option (the “Stock Option”) to purchase on or prior to the Expiration Date specified above all or part of the number of
shares of Common Stock, par value $0.001 per share (the “Stock”), of the Company specified above at the Option Exercise Price per Share specified above subject to the terms and conditions set forth herein and in the Plan. 

1. Exercisability Schedule. No portion of this Stock Option may be exercised until such portion shall have become exercisable. Except
as set forth below, and subject to the discretion of the Administrator (as defined in Section 2 of the Plan) to accelerate the exercisability schedule hereunder, this Stock Option shall be exercisable with respect to the following number of
Option Shares on the dates indicated so long as the Optionee remains an employee of the Company or a Subsidiary on such dates: 
  

			
	 Incremental 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 or times prior to the close of business on the Expiration
Date, subject to the provisions hereof and of the Plan. 

 2. Manner of Exercise. 

(a) The Optionee may exercise this Stock Option only in the following manner: from time to time on or prior to the Expiration Date of this
Stock Option, the Optionee may give written notice to the Administrator of his or her election to purchase some or all of the Option Shares purchasable at the time of such notice. This notice shall specify the number of Option Shares to be
purchased. 
 Payment of the purchase price for the Option Shares may be made by one or more of the following methods: (i) in cash, by
certified or bank check or other instrument acceptable to the Administrator; (ii) through the delivery (or attestation to the ownership) of shares of Stock 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 any restrictions under any Company plan and that otherwise satisfy any holding periods as may be required by the Administrator; or (iii) 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 to pay the option purchase price, provided that in the event the Optionee chooses to
pay the option 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 Administrator shall prescribe as a condition of such payment
procedure; or (iv) a combination of (i), (ii) and (iii) above. Payment instruments will be received subject to collection. 
 The
transfer to the Optionee on the records of the Company or of the transfer agent of the Option Shares will be contingent upon (i) the Company’s receipt from the Optionee 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
Optionee 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 Optionee 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 Optionee on the records of the Company or
of the transfer agent upon compliance to the satisfaction of the Administrator with all requirements under applicable laws or regulations in connection with such transfer and with the requirements hereof and of the Plan. The determination of the
Administrator as to such compliance shall be final and binding on the Optionee. The Optionee 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 exercised pursuant to the terms hereof, the Company or the transfer agent shall have transferred the shares to the Optionee, and the Optionee’s name shall have been entered as the stockholder of
record on the books of the Company. Thereupon, the Optionee shall have full voting, dividend and other ownership rights with respect to such shares of Stock. 

  
 2 

 (c) 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. 

(d) Notwithstanding any other provision hereof or of the Plan, no portion of this Stock Option shall be exercisable after the Expiration Date
hereof. 
 3. Termination of Employment. If the Optionee’s employment by the Company or a Subsidiary (as defined in the Plan) 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 Optionee’s employment terminates by reason of the Optionee’s 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 Optionee’s legal representative or legatee for a period of 12 months from the date of death or until the Expiration Date, if earlier. Any portion of this Stock Option that is not exercisable on the date of death shall terminate
immediately and be of no further force or effect. 
 (b) Termination Due to Disability. If the Optionee’s employment terminates
by reason of the Optionee’s 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
Optionee for a period of 12 months from the date of disability or until the Expiration Date, if earlier. Any portion of this Stock Option that is not exercisable on the date of disability shall terminate immediately and be of no further force or
effect. 
 (c) Termination for Cause. If the Optionee’s employment terminates for Cause, any portion of this Stock Option
outstanding on such date shall terminate immediately and be of no further force and effect. For purposes hereof, “Cause” shall mean, unless otherwise provided in an employment agreement between the Company and the Optionee, a determination
by the Administrator that the Optionee shall be dismissed as a result of (i) any material breach by the Optionee of any agreement between the Optionee and the Company; (ii) the conviction of, indictment for or plea of nolo
contendere by the Optionee to a felony or a crime involving moral turpitude; or (iii) any material misconduct or willful and deliberate non-performance (other than by reason of disability) by the Optionee
of the Optionee’s duties to the Company. 
 (d) Other Termination. If the Optionee’s employment terminates for any reason
other than the Optionee’s death, the Optionee’s disability, or Cause, and unless otherwise determined by the Administrator, any portion of this Stock Option outstanding on such date may be exercised, to the extent exercisable on the date
of termination, for a period of three months from the date of termination or until the Expiration Date, if earlier. 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. 

  
 3 

 The Administrator’s determination of the reason for termination of the Optionee’s
employment shall be conclusive and binding on the Optionee 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 Optionee, 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 Optionee’s lifetime, only by the Optionee, and thereafter, only by the Optionee’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 Internal Revenue Code of 1986, as amended (the “Code”), but the Company does not represent or warrant that this Stock Option qualifies as such. The Optionee 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 Optionee 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 Optionee 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 Administrator 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 minimum required tax withholding obligation to be satisfied, in whole or in part, by
withholding from shares of Stock to be issued to the Optionee a number of shares of Stock with an aggregate Fair Market Value that would satisfy the minimum 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 Optionee 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 Optionee 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. 

  
 4 

 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 Optionee (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information; (ii) waives any privacy rights the Optionee 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 Optionee 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 Optionee 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. 

 

			
	UNUM THERAPEUTICS INC.

 
			
		
	By:	 	  

		 	Title:

 The foregoing Agreement is hereby accepted and the terms and conditions thereof hereby agreed to by the undersigned.
Electronic acceptance of this Agreement pursuant to the Company’s instructions to the Optionee (including through an online acceptance process) is acceptable. 
  

									
	Dated:                                     
                                   	 		 		 	  

		 		 		 	Optionee’s Signature
				
		 		 		 	Optionee’s name and address:
				
		 		 		 	  

				
		 		 		 	  

				
		 		 		 	  

  
 5 

 NON-QUALIFIED STOCK OPTION AGREEMENT 

FOR COMPANY EMPLOYEES 

UNDER THE UNUM THERAPEUTICS INC. 

2018 STOCK OPTION AND INCENTIVE PLAN 
  

									
	Name of Optionee:	  		  	  

					
	No. of Option Shares:	  		  	  
	  		  	
					
	Option Exercise Price per Share:	  	$	  	  
	  		  	
					
	Grant Date:	  		  	  
	  		  	
					
	Expiration Date:	  		  	  
	  		  	

 Pursuant to the Unum Therapeutics Inc. 2018 Stock Option and Incentive Plan as amended through the date hereof
(the “Plan”), Unum Therapeutics Inc. (the “Company”) hereby grants to the Optionee named above an option (the “Stock Option”) to purchase on or prior to the Expiration Date specified above all or part of the number of
shares of Common Stock, par value $0.001 per share (the “Stock”) of the Company specified above at the Option Exercise Price per Share specified above subject to the terms and conditions set forth herein and in the Plan. This Stock Option
is not intended to be an “incentive stock option” under Section 422 of the Internal Revenue Code of 1986, as amended. 
 1.
Exercisability Schedule. No portion of this Stock Option may be exercised until such portion shall have become exercisable. Except as set forth below, and subject to the discretion of the Administrator (as defined in Section 2 of the
Plan) to accelerate the exercisability schedule hereunder, this Stock Option shall be exercisable with respect to the following number of Option Shares on the dates indicated so long as Optionee remains an employee of the Company or a Subsidiary on
such dates: 
  

			
	 Incremental Number of

Option Shares Exercisable
	  	Exercisability Date
		
	 _____________ (___%)
	  	                            
	 _____________ (___%)
	  	                            
	 _____________ (___%)
	  	                            
	 _____________ (___%)
	  	                            
	 _____________ (___%)
	  	                            

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

 2. Manner of Exercise. 

(a) The Optionee may exercise this Stock Option only in the following manner: from time to time on or prior to the Expiration Date of this
Stock Option, the Optionee may give written notice to the Administrator of his or her election to purchase some or all of the Option Shares purchasable at the time of such notice. This notice shall specify the number of Option Shares to be
purchased. 
 Payment of the purchase price for the Option Shares may be made by one or more of the following methods: (i) in cash, by
certified or bank check or other instrument acceptable to the Administrator; (ii) through the delivery (or attestation to the ownership) of shares of Stock 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 any restrictions under any Company plan and that otherwise satisfy any holding periods as may be required by the Administrator; (iii) 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 to pay the option purchase price, provided that in the event the Optionee chooses to
pay the option 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 Administrator shall prescribe as a condition of such payment
procedure; (iv) 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; or (v) a combination of (i), (ii), (iii) and (iv) above. Payment instruments will be received subject to collection. 

The transfer to the Optionee on the records of the Company or of the transfer agent of the Option Shares will be contingent upon (i) the
Company’s receipt from the Optionee 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 Optionee 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 Optionee 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 Optionee on the records of the Company or of the transfer agent upon compliance to the satisfaction of the Administrator with all requirements under applicable laws or
regulations in connection with such transfer and with the requirements hereof and of the Plan. The determination of the Administrator as to such compliance shall be final and binding on the Optionee. The Optionee 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 exercised pursuant to the terms hereof, the Company or the transfer agent shall have
transferred the shares to the Optionee, and the Optionee’s name shall have been entered as the stockholder of record on the books of the Company. Thereupon, the Optionee shall have full voting, dividend and other ownership rights with respect
to such shares of Stock. 

  
 2 

 (c) 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. 

(d) Notwithstanding any other provision hereof or of the Plan, no portion of this Stock Option shall be exercisable after the Expiration Date
hereof. 
 3. Termination of Employment. If the Optionee’s employment by the Company or a Subsidiary (as defined in the Plan) 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 Optionee’s employment terminates by reason of the Optionee’s 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 Optionee’s legal representative or legatee for a period of 12 months from the date of death or until the Expiration Date, if earlier. Any portion of this Stock Option that is not exercisable on the date of death shall terminate
immediately and be of no further force or effect. 
 (b) Termination Due to Disability. If the Optionee’s employment terminates
by reason of the Optionee’s 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
Optionee for a period of 12 months from the date of disability or until the Expiration Date, if earlier. Any portion of this Stock Option that is not exercisable on the date of disability shall terminate immediately and be of no further force or
effect. 
 (c) Termination for Cause. If the Optionee’s employment terminates for Cause, any portion of this Stock Option
outstanding on such date shall terminate immediately and be of no further force and effect. For purposes hereof, “Cause” shall mean, unless otherwise provided in an employment agreement between the Company and the Optionee, a determination
by the Administrator that the Optionee shall be dismissed as a result of (i) any material breach by the Optionee of any agreement between the Optionee and the Company; (ii) the conviction of, indictment for or plea of nolo contendere by
the Optionee to a felony or a crime involving moral turpitude; or (iii) any material misconduct or willful and deliberate non-performance (other than by reason of disability) by the Optionee of the
Optionee’s duties to the Company. 
 (d) Other Termination. If the Optionee’s employment terminates for any reason other
than the Optionee’s death, the Optionee’s disability or Cause, and unless otherwise determined by the Administrator, any portion of this Stock Option outstanding on such date may be exercised, to the extent exercisable on the date of
termination, for a period of three months from the date of termination or until the Expiration Date, if earlier. 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. 

  
 3 

 The Administrator’s determination of the reason for termination of the Optionee’s
employment shall be conclusive and binding on the Optionee 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 Optionee, 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 Optionee’s lifetime, only by the Optionee, and thereafter, only by the Optionee’s legal representative or legatee. 

6. Tax Withholding. The Optionee 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 Administrator 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 minimum required tax withholding obligation to be satisfied, in whole or in part, by withholding from shares of Stock to be issued to the Optionee a number of shares of Stock with an aggregate Fair Market Value that would
satisfy the minimum 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 Optionee 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
Optionee 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. 
 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 Optionee (i) authorizes the Company to collect, process, register and transfer to the Relevant Companies all Relevant Information;
(ii) waives any privacy rights the Optionee 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 Optionee shall have access to, and the right to change, the Relevant Information. Relevant Information will only be used in accordance with applicable
law. 

  
 4 

 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 Optionee 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. 

 

			
	UNUM THERAPEUTICS INC.
		
	By:	 	  

		 	Title:

 The foregoing Agreement is hereby accepted and the terms and conditions thereof hereby agreed to by the undersigned.
Electronic acceptance of this Agreement pursuant to the Company’s instructions to the Optionee (including through an online acceptance process) is acceptable. 
  

									
	Dated:
                                         
                               	 		 		 	  

		 		 		 	Optionee’s Signature
				
		 		 		 	Optionee’s name and address:
				
		 		 		 	  

				
		 		 		 	  

				
		 		 		 	  

  
 5

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