Sec Form 3 Filing - LYNCH DANIEL @ Xilio Therapeutics, Inc. - 2021-10-21

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person LYNCH DANIEL 2. Issuer Name and Ticker or Trading Symbol Xilio Therapeutics, Inc. [ XLO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O XILIO THERAPEUTICS, INC., 828 WINTER STREET, SUITE 300 3. Date of Earliest Transaction (MM/DD/YY) 10/21/2021 (Street) WALTHAM,, MA02451 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Option (right to buy) $ 5.51 ( 1 ) 07/22/2030 Common Stock 134,797 D Stock Option (right to buy) $ 5.89 ( 2 ) 03/10/2031 Common Stock 200,597 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other LYNCH DANIEL C/O XILIO THERAPEUTICS, INC. 828 WINTER STREET, SUITE 300 WALTHAM,, MA02451 X X Signatures /s/ Chris Frankenfield, Attorney-in-Fact 10/21/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The option was granted on July 23, 2020 for 134,797 shares. The underlying shares began vesting on June 11, 2020 and shall continue to vest in equal monthly installments thereafter until June 11, 2024. ( 2 )The option was granted on March 11, 2021 for 200,597 shares. The underlying shares began vesting on June 11, 2020 and shall continue to vest in equal monthly installments thereafter until June 11, 2024.

Remarks: Exhibit Index: 24.1 Power of Attorney

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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