Xilio Therapeutics (XLO) 10-Q 2023 Q2 Quarterly report

EXHIBIT 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with this Quarterly Report on Form 10-Q of Xilio Therapeutics, Inc. (the “Company”) for the three months ended June 30, 2023 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), we, René Russo, Chief Executive Officer of the Company, and Kevin Brennan, Senior Vice President, Finance and Accounting, of the Company, certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, to our knowledge that:

(1) The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

A signed original of this written statement required by Section 906 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.

/s/ René Russo	/s/ Kevin Brennan
Name: René Russo	Name: Kevin Brennan
Title: Chief Executive Officer	Title: Senior Vice President, Finance and Accounting
(Principal Executive Officer)	(Principal Financial and Accounting Officer)
Date: August 14, 2023	Date: August 14, 2023