Exhibit 10.5


 


April 6, 2021


 


CM Life Sciences III Inc.


c/o Corvex Management LP


667 Madison Avenue


New York, New York 10065


 


Re: Initial
Public Offering


 


Ladies and Gentlemen:


 


This letter (this “Letter
Agreement”) is being delivered to you in accordance with the Underwriting Agreement (the “Underwriting Agreement”)
entered into by and between CM Life Sciences III Inc., a Delaware corporation (the “Company”), and Jefferies
LLC and Cowen and Company, LLC, as representatives of the several underwriters (the “Underwriters”),
relating to an underwritten initial public offering (the “Public Offering”), of up to 55,200,000 of the
Company’s units (including up to 7,200,000 units that may be purchased to cover over-allotments, if any) (the “Units”),
each comprised of one share of the Company’s Class A common stock, par value $0.0001 per share (the “Class A Common
Stock”), and one-fifth of one redeemable warrant. Each whole warrant (each, a “Public Warrant”)
entitles the holder thereof to purchase one share of Class A Common Stock at a price of $11.50 per share, subject to adjustment as described
in the Prospectus (as defined below). The Units will be sold in the Public Offering pursuant to a registration statement on Form S-1 and
prospectus (the “Prospectus”) filed by the Company with the U.S. Securities and Exchange Commission (the “Commission”)
and the Company has applied to have the Units listed on the New York Stock Exchange. Certain capitalized terms used herein are defined
in paragraph 11 hereof.


 


In order to induce the Company
and the Underwriters to enter into the Underwriting Agreement and to proceed with the Public Offering and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, each of CMLS Holdings III LLC, a Delaware limited liability
company (the “Sponsor”), and the undersigned individuals or entities, each of whom is a member of the Company’s
board of directors and/or management team and/or one or more entities controlled by them (each of the undersigned individuals or entities,
an “Insider” and collectively, the “Insiders”), hereby agrees with the Company
as follows:


 


1. The
Sponsor and each Insider agrees that if the Company seeks stockholder approval of a proposed Business Combination, then in connection
with such proposed Business Combination, it, he or she shall (i) vote any shares of Common Stock (as defined below) owned by it, him or
her in favor of any proposed Business Combination and (ii) not redeem any shares of Common Stock owned by it, him or her in connection
with such stockholder approval. If the Company seeks to consummate a proposed Business Combination by engaging in a tender offer, the
Sponsor and each Insider agrees that it, he or she will not sell or tender any shares of Common Stock owned by it, him or her in connection
therewith.


 


2. The
Sponsor and each Insider hereby agrees that in the event that the Company fails to consummate a Business Combination within 24 months
from the closing of the Public Offering, or such later period approved by the Company’s stockholders in accordance with the Company’s
amended and restated certificate of incorporation (as it may be amended from time to time, the “Charter”),
the Sponsor and each Insider shall take all reasonable steps to cause the Company to (i) cease all operations except for the purpose of
winding up, (ii) as promptly as reasonably possible but not more than ten business days thereafter, redeem 100% of the shares of Class
A Common Stock sold as part of the Units in the Public Offering (the “Offering Shares”), at a per-share
price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account (as defined below), including interest earned
on the funds held in the Trust Account and not previously released to the Company to pay its taxes (less up to $100,000 of interest to
pay dissolution expenses), divided by the number of then outstanding Offering Shares, which redemption will completely extinguish all
Public Stockholders’ (as defined below) rights as stockholders (including the right to receive further liquidating distributions,
if any), and (iii) as promptly as reasonably possible following such redemption, subject to the approval of the Company’s remaining
stockholders and the Company’s board of directors, liquidate and dissolve, subject in each case to the Company’s obligations
under Delaware law to provide for claims of creditors and other requirements of applicable law. The Sponsor and each Insider agrees to
not propose any amendment to the Charter to modify the substance or timing of the Company’s obligation to redeem 100% of the Offering
Shares if the Company does not complete a Business Combination within the required time period set forth in the Charter or with respect
to any other material provisions relating to stockholders’ rights or pre-initial business combination activity, unless the Company
provides its Public Stockholders with the opportunity to redeem their Offering Shares upon approval of any such amendment at a per-share
price, payable in cash, equal to the aggregate amount then on deposit in the Trust Account, including interest earned on the funds held
in the Trust Account and not previously released to the Company to pay its taxes, divided by the number of then outstanding Offering Shares.


 


The Sponsor and each Insider
acknowledges that it, he or she has no right, title, interest or claim of any kind in or to any monies held in the Trust Account or any
other asset of the Company as a result of any liquidation of the Company with respect to the Founder Shares held by it, him or her. The
Sponsor and each Insider hereby further waives, with respect to any shares of Common Stock held by it, him or her, if any, any redemption
rights it, he or she may have in connection with (A) the consummation of a Business Combination, including, without limitation, any such
rights available in the context of a stockholder vote to approve such Business Combination, or (B) a stockholder vote to approve an amendment
to the Charter to modify the substance or timing of the Company’s obligation to redeem 100% of the Offering Shares if the Company
has not consummated a Business Combination within the time period set forth in the Charter or with respect to any other material provisions
relating to stockholders’ rights or pre-initial business combination activity or in the context of a tender offer made by the Company
to purchase Offering Shares (although the Sponsor, the Insiders and their respective affiliates shall be entitled to redemption and liquidation
rights with respect to any Offering Shares it or they hold if the Company fails to consummate a Business Combination within the time period
set forth in the Charter).


 






     


     


    

 


3. Notwithstanding
the provisions set forth in paragraphs in 7(a) and 7(b), during the period commencing on the effective date of the Underwriting Agreement
and ending 180 days after such date, the Sponsor and each Insider shall not, without the prior written consent of the Underwriters, (i)
sell, offer to sell, contract or agree to sell, hypothecate, pledge, grant any option to purchase or otherwise dispose of or agree to
dispose of, directly or indirectly, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position
within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”),
and the rules and regulations of the Commission promulgated thereunder, with respect to, any Units, shares of Class A Common Stock (including,
but not limited to, Founder Shares), Warrants (as defined below) or any securities convertible into, or exercisable, or exchangeable for,
shares of Class A Common Stock owned by it, him or her, (ii) enter into any swap or other arrangement that transfers to another, in whole
or in part, any of the economic consequences of ownership of any Units, shares of Common Stock (including, but not limited to, Founder
Shares), Warrants or any securities convertible into, or exercisable, or exchangeable for, shares of Common Stock owned by it, him or
her, whether any such transaction is to be settled by delivery of such securities, in cash or otherwise, or (iii) publicly announce any
intention to effect any transaction specified in clause (i) or (ii); provided, however, all of the foregoing does not apply to the forfeiture
of any Founder Shares pursuant to their terms or any transfer of Founder Shares to any current or future independent director of the company
(as long as such current or future independent director transferee is subject to this Letter Agreement or executes an agreement substantially
identical to the terms of this Letter Agreement, as applicable to directors and officers at the time of such transfer; and as long as,
to the extent any Section 16 reporting obligation is triggered as a result of such transfer, any related Section 16 filing includes a
practical explanation as to the nature of the transfer). Each of the Insiders and the Sponsor acknowledges and agrees that, prior to the
effective date of any release or waiver, of the restrictions set forth in this paragraph 3 or paragraph 7 below, the Company may announce
the impending release or waiver by press release through a major news service at least two business days before the effective date of
the release or waiver. The provisions of this paragraph will not apply if the release or waiver is effected solely to permit a transfer
not for consideration and the transferee has agreed in writing to be bound by the same terms described in this Letter Agreement to the
extent and for the duration that such terms remain in effect at the time of the transfer.


 


4. In the event of the liquidation
of the Trust Account upon the failure of the Company to consummate its initial Business Combination within the time period set forth
in the Charter, the Sponsor (the “Indemnitor”) agrees to indemnify and hold harmless the Company against any
and all loss, liability, claim, damage and expense whatsoever (including, but not limited to, any and all legal or other expenses reasonably
incurred in investigating, preparing or defending against any litigation, whether pending or threatened) to which the Company may become
subject as a result of any claim by (i) any third party for services rendered (other than the independent registered public accounting
firm) or products sold to the Company or (ii) any prospective target business with which the Company has entered into a written letter
of intent, confidentiality or other similar agreement or Business Combination agreement (a “Target”);
provided, however, that such indemnification of the Company by the Indemnitor (x) shall apply only to the extent necessary to ensure
that such claims by a third party for services rendered (other than the independent registered public accounting firm) or products sold
to the Company or a Target do not reduce the amount of funds in the Trust Account to below the lesser of (i) $10.00 per Offering Share
and (ii) the actual amount per Offering Share held in the Trust Account as of the date of the liquidation of the Trust Account, if less
than $10.00 per Offering Share is then held in the Trust Account due to reductions in the value of the trust assets, less taxes payable,
(y) shall not apply to any claims by a third party or a Target which executed a waiver of any and all rights to the monies held in the
Trust Account (whether or not such waiver is enforceable) and (z) shall not apply to any claims under the Company’s indemnity of
the Underwriters against certain liabilities, including liabilities under the Securities Act of 1933, as amended. The Indemnitor shall
have the right to defend against any such claim with counsel of its choice reasonably satisfactory to the Company if, within 15 days
following written receipt of notice of the claim to the Indemnitor, the Indemnitor notifies the Company in writing that it shall undertake
such defense.


 


5. To
the extent that the Underwriters does not exercise its over-allotment option to purchase up to an additional 7,200,000 Units within 45
days from the date of the Prospectus (and as further described in the Prospectus), the Sponsor agrees to forfeit, at no cost, a number
of Founder Shares in the aggregate equal to 1,800,000 multiplied by a fraction, (i) the numerator of which is 7,200,000 minus the number
of Units purchased by the Underwriters upon the exercise of their over-allotment option, and (ii) the denominator of which is 7,200,000.
The forfeiture will be adjusted to the extent that the over-allotment option is not exercised in full by the Underwriters so that the
Founder Shares will represent an aggregate of 20.0% of the Company’s issued and outstanding shares of Class A Common Stock after
the Public Offering (not including shares of Class A Common Stock underlying the Public Warrants or Private Placement Warrants (as defined
below)). The Sponsor further agrees that to the extent that the size of the Public Offering is increased or decreased, the Company will
purchase or sell Units or effect a stock dividend or share contribution back to capital, as applicable, immediately prior to the consummation
of the Public Offering in such amount as to maintain the number of Founder Shares at 20.0% of its issued and outstanding Common Stock
upon the consummation of the Public Offering. In connection with such increase or decrease in the size of the Public Offering, (A) the
references to 7,200,000 in the numerator and denominator of the formula in the first sentence of this paragraph shall be changed to a
number equal to 15% of the number of Offering Shares included in the Units issued in the Public Offering and (B) the reference to 1,800,000
in the formula set forth in the first sentence of this paragraph shall be adjusted to such number of Founder Shares that the Sponsor would
have to surrender to the Company in order for the number of Founder Shares to equal an aggregate of 20.0% of the Company’s issued
and outstanding shares of Class A Common Stock after the Public Offering (not including shares of Class A Common Stock underlying the
Public Warrants or Private Placement Warrants).


 


6. The
Sponsor and each Insider hereby agrees and acknowledges that: (i) the Underwriters and the Company would be irreparably injured in the
event of a breach by such Sponsor or an Insider of its, his or her obligations under paragraphs 1, 2, 3, 4, 5, 7(a), 7(b) and 9, as applicable,
of this Letter Agreement (ii) monetary damages may not be an adequate remedy for such breach and (iii) the non-breaching party shall be
entitled to injunctive relief, in addition to any other remedy that such party may have in law or in equity, in the event of such breach.


 


7. (a)
The Sponsor and each Insider agrees that it, he or she shall not Transfer (as defined below) any Founder Shares (or any shares of Class
A Common Stock issuable upon conversion thereof) until the earlier of (A) one year after the completion of the Company’s initial
Business Combination and (B) subsequent to the Business Combination, (x) if the closing price of the Class A Common Stock equals or exceeds
$12.00 per share (as adjusted for stock splits, stock dividends, reorganizations, recapitalizations and the like) for any 20 trading days
within any 30-trading day period commencing at least 150 days after the Company’s initial Business Combination or (y) the date following
the completion of the Company’s initial Business Combination on which the Company completes a liquidation, merger, capital stock
exchange, reorganization or other similar transaction that results in all of the Company’s stockholders having the right to exchange
their shares of Class A Common Stock for cash, securities or other property (the “Founder Shares Lock-up Period”).


 


(b) The
Sponsor and each Insider agrees that it, he or she shall not Transfer any Private Placement Warrants (or any share of Class A Common Stock
issued or issuable upon the exercise of the Private Placement Warrants), until 30 days after the completion of a Business Combination
(the “Private Placement Warrants Lock-up Period”, together with the Founder Shares Lock-up Period, the “Lock-up
Periods”).


 






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(c) Notwithstanding
the provisions set forth in paragraphs 7(a) and (b), Transfers of the Founder Shares, Private Placement Warrants and shares of Class A
Common Stock issued or issuable upon the exercise or conversion of the Private Placement Warrants or the Founder Shares that are held
by the Sponsor, any Insider or any of their permitted transferees (that have complied with this paragraph 7(c)), are permitted (a) to
the Company’s officers or directors, any affiliates or family members of any of the Company’s officers or directors, any members
or partners of the Sponsor or their affiliates (including members of the Sponsor’s members), any affiliates of the Sponsor, or any
employees of such affiliates; (b) in the case of an individual, by gift to a member of such individual’s immediate family or to
a trust, the beneficiary of which is a member of such individual’s immediate family, an affiliate of such individual or to a charitable
organization; (c) in the case of an individual, by virtue of laws of descent and distribution upon death of such individual; (d) in the
case of an individual, pursuant to a qualified domestic relations order; (e) by private sales or transfers made in connection with any
forward purchase agreement or similar arrangement or in connection with the consummation of an initial Business Combination at prices
no greater than the price at which the securities were originally purchased; (f) by virtue of the laws of the State of Delaware or the
Sponsor’s organizational documents upon liquidation or dissolution of the Sponsor; (g) to the Company for no value for cancellation
in connection with the consummation of an initial Business Combination; (h) in the event of the Company’s liquidation prior to the
consummation of an initial Business Combination; or (i) in the event of the Company’s completion of a liquidation, merger, capital
stock exchange or other similar transaction which results in all of the Company’s stockholders having the right to exchange their
shares of Class A Common Stock for cash, securities or other property subsequent to the Company’s completion of an initial Business
Combination; provided, however, that in the case of clauses (a) through (f), these permitted transferees must enter into
a written agreement with the Company agreeing to be bound by the transfer restrictions herein and the other restrictions contained in
this Agreement (including provisions relating to voting, the Trust Account and liquidating distributions).


 


8. The
Sponsor and each Insider represents and warrants that it, he or she has never been suspended or expelled from membership in any securities
or commodities exchange or association or had a securities or commodities license or registration denied, suspended or revoked. Each Insider’s
biographical information furnished to the Company (including any such information included in the Prospectus) is true and accurate in
all material respects and does not omit any material information with respect to such Insider’s background. The Sponsor and each
Insider represents and warrants that the questionnaire it, he or she furnished to the Company is true and accurate in all material respects.
The Sponsor and each Insider represents and warrants that: it, he or she is not subject to or a respondent in any legal action for, any
injunction, cease-and-desist order or order or stipulation to desist or refrain from any act or practice relating to the offering of securities
in any jurisdiction; it, he or she has never been convicted of, or pleaded guilty to, any crime (i) involving fraud, (ii) relating to
any financial transaction or handling of funds of another person, or (iii) pertaining to any dealings in any securities and it, he or
she is not currently a defendant in any such criminal proceeding.


 


9. Except
as disclosed in the Prospectus, neither the Sponsor nor any officer, nor any affiliate of the Sponsor or any officer, nor any director
of the Company, shall receive from the Company any finder’s fee, reimbursement, consulting fee, non-cash payments, monies in respect
of any repayment of a loan or other compensation prior to, or in connection with any services rendered in order to effectuate, the consummation
of the Company’s initial Business Combination (regardless of the type of transaction that it is), other than the following, none
of which will be made from the proceeds held in the Trust Account prior to the completion of the initial Business Combination: repayment
of a loan and advances up to an aggregate of $300,000 made to the Company by the Sponsor; reimbursement for any reasonable out-of-pocket
expenses related to identifying, investigating, negotiating and completing an initial Business Combination; and repayment of loans, if
any, and on such terms as to be determined by the Company from time to time, made by the Sponsor or an affiliate of the Sponsor or any
of the Company’s officers or directors to finance transaction costs in connection with an intended initial Business Combination,
provided, that, if the Company does not consummate an initial Business Combination, a portion of the working capital held outside the
Trust Account may be used by the Company to repay such loaned amounts so long as no proceeds from the Trust Account are used for such
repayment. Up to $1,500,000 of such loans may be convertible into warrants of the post-Business Combination entity at a price of $1.50
per warrant at the option of the lender. Such warrants would be identical to the Private Placement Warrants, including as to exercise
price, exercisability and exercise period.


 


10. The
Sponsor and each Insider has full right and power, without violating any agreement to which it is bound (including, without limitation,
any non-competition or non-solicitation agreement with any employer or former employer), to enter into this Letter Agreement and, as applicable,
to serve as an officer and/or director on the board of directors of the Company and hereby consents to being named in the Prospectus as
an officer and/or director of the Company.


 


11. As
used herein, (i) “Business Combination” shall mean a merger, capital stock exchange, asset acquisition, stock
purchase, reorganization or similar business combination, involving the Company and one or more businesses; (ii) “Common Stock”
shall mean the Class A Common Stock and Class B common stock, par value $0.0001 per share, of the Company (“Class B Common
Stock”); (iii) “Founder Shares” shall mean the 13,800,000 shares of Class B Common Stock issued
and outstanding immediately prior to the consummation of the Public Offering (up to 1,800,000 shares of which are subject to forfeiture
by the Sponsor if the over-allotment option is not exercised by the Underwriters); (iv) “Initial Stockholders”
shall mean the Sponsor and any Insider that holds Founder Shares; (v) “Private Placement Warrants” shall mean
the 7,733,333 warrants (or 8,693,333 warrants if the over-allotment option is exercised in full) that the Sponsor and certain Insiders
have agreed to purchase for an aggregate purchase price of $11,600,000 (or $13,040,000 if the over-allotment option is exercised in full),
or $1.50 per warrant, in a private placement that shall occur simultaneously with the consummation of the Public Offering; (vi) “Public
Stockholders” shall mean the holders of securities issued in the Public Offering; (vii) “Trust Account”
shall mean the trust fund into which a portion of the net proceeds of the Public Offering and the sale of the Private Placement Warrants
shall be deposited; (viii) “Transfer” shall mean the (a) sale of, offer to sell, contract or agreement to sell,
hypothecate, pledge, grant of any option to purchase or otherwise dispose of or agreement to dispose of, directly or indirectly, or establishment
or increase of a put equivalent position or liquidation with respect to or decrease of a call equivalent position within the meaning of
Section 16 of the Exchange Act, and the rules and regulations of the Commission promulgated thereunder with respect to, any security,
(b) entry into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership
of any security, whether any such transaction is to be settled by delivery of such securities, in cash or otherwise, or (c) public announcement
of any intention to effect any transaction specified in clause (a) or (b); and (ix) “Warrants” shall mean the
Private Placement Warrants and Public Warrants.


 






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12. The
Company will maintain an insurance policy or policies providing directors’ and officers’ liability insurance, and each of
the Company’s directors and officers shall be covered by such policy or policies, in accordance with its or their terms, to the
maximum extent of the coverage available for any of the Company’s directors or officers.


 


13. This
Letter Agreement constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter hereof and
supersedes all prior understandings, agreements, or representations by or among the parties hereto, written or oral, to the extent they
relate in any way to the subject matter hereof or the transactions contemplated hereby. This Letter Agreement may not be changed, amended,
modified or waived (other than to correct a typographical error) as to any particular provision, except by a written instrument executed
by all parties hereto.


 


14. No
party hereto may assign either this Letter Agreement or any of its rights, interests, or obligations hereunder without the prior written
consent of the other parties. Any purported assignment in violation of this paragraph shall be void and ineffectual and shall not operate
to transfer or assign any interest or title to the purported assignee. This Letter Agreement shall be binding on the Sponsor and each
Insider and their respective successors, heirs and assigns and permitted transferees.


 


15. Nothing
in this Letter Agreement shall be construed to confer upon, or give to, any person or corporation other than the parties hereto any right,
remedy or claim under or by reason of this Letter Agreement or of any covenant, condition, stipulation, promise or agreement hereof. All
covenants, conditions, stipulations, promises and agreements contained in this Letter Agreement shall be for the sole and exclusive benefit
of the parties hereto and their successors, heirs, personal representatives and assigns and permitted transferees.


 


16. This
Letter Agreement may be executed in any number of original or facsimile counterparts and each of such counterparts shall for all purposes
be deemed to be an original, and all such counterparts shall together constitute but one and the same instrument.


 


17. This
Letter Agreement shall be deemed severable, and the invalidity or unenforceability of any term or provision hereof shall not affect the
validity or enforceability of this Letter Agreement or of any other term or provision hereof. Furthermore, in lieu of any such invalid
or unenforceable term or provision, the parties hereto intend that there shall be added as a part of this Letter Agreement a provision
as similar in terms to such invalid or unenforceable provision as may be possible and be valid and enforceable.


 


18. This
Letter Agreement shall be governed by and construed and enforced in accordance with the laws of the State of New York. The parties hereto
(i) all agree that any action, proceeding, claim or dispute arising out of, or relating in any way to, this Letter Agreement shall be
brought and enforced in the courts of New York City, in the State of New York, and irrevocably submit to such jurisdiction and venue,
which jurisdiction and venue shall be exclusive and (ii) waive any objection to such exclusive jurisdiction and venue or that such courts
represent an inconvenient forum.


 


19. Any
notice, consent or request to be given in connection with any of the terms or provisions of this Letter Agreement shall be in writing
and shall be sent by express mail or similar private courier service, by certified mail (return receipt requested), by hand delivery or
facsimile transmission.


 


20. This
Letter Agreement shall terminate on the earlier of (i) the expiration of the Lock-up Periods and (ii) the liquidation of the Company;
provided, however, that this Letter Agreement shall earlier terminate in the event that the Public Offering is not consummated and closed
by December 31, 2021; provided further that paragraph 4 of this Letter Agreement shall survive such liquidation.


 


[Signature Page Follows]


 






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	 	Sincerely,
	 	 	 
	 	CMLS HOLDINGS III LLC
	 	 	 
	 	By:	/s/ Keith Meister
	 		Name: Keith Meister
	 		Title: Manager
	 	 	 
	 	/s/ Eli Casdin
	 	Name: Eli Casdin
	 	 
	 	/s/ Keith Meister
	 	Name: Keith Meister
	 	 
	 	/s/ Brian Emes
	 	Name: Brian Emes
	 	 
	 	/s/ Shaun Rodriguez
	 	Name: Shaun Rodriguez
	 	 
	 	/s/ Christian Henry
	 	Name: Christian Henry
	 	 
	 	/s/ Kwame Owusu-Kesse
	 	Name: Kwame Owusu-Kesse
	 	 
	 	/s/ Chad Robins
	 	Name: Chad Robins
	 	 
	 	/s/ Harlan Robins
	 	Name: Harlan Robins



 


	Acknowledged and Agreed:	 
	CM LIFE SCIENCES III INC.	 
	By: 	/s/ Brian Emes	 
	 	Name:  	Brian Emes	 
	 	Title:	Chief Financial Officer and Secretary	 



 


 


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