X0202 SCHEDULE 13G 0001055951 XXXXXXXX LIVE Common Stock, par value $0.0001 per share 03/31/2026 0001840233 Xilio Therapeutics, Inc. 28422T209 828 Winter Street Waltham MA 02451 Rule 13d-1(b) ORBIMED ADVISORS LLC DE 0.00 642000.00 0.00 642000.00 642000.00 N 9.99 IA OrbiMed Capital GP X LLC DE 0.00 481500.00 0.00 481500.00 481500.00 N 7.49 OO Xilio Therapeutics, Inc. 828 Winter Street Waltham, MA 02451 OrbiMed Advisors LLC ("OrbiMed Advisors"), a limited liability company organized under the laws of Delaware and a registered investment adviser under the Investment Advisers Act of 1940, as amended. OrbiMed Capital GP X LLC ("OrbiMed GP" and together with OrbiMed Advisors, the "Reporting Persons"), a limited liability company organized under the laws of Delaware. 601 Lexington Avenue, 54th Floor New York, NY 10022 Please refer to Item 4 on each cover sheet for each filing person. N IA OrbiMed Advisors: 642,000 OrbiMed GP: 481,500 OrbiMed Advisors: 9.99% OrbiMed GP: 7.49% OrbiMed Advisors: 0 OrbiMed GP: 0 OrbiMed Advisors: 642,000 OrbiMed GP: 481,500 OrbiMed Advisors: 0 OrbiMed GP: 0 OrbiMed Advisors: 642,000 OrbiMed GP: 481,500 Y N The Reporting Persons hold 9.99% of the shares of Common Stock upon conversion of warrants in the aggregate on behalf of other persons who have the right to receive or the power to direct the receipt of dividends from, or proceeds from the sale of, such securities. OrbiMed Advisors exercises investment and voting power over the shares of Common Stock through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares of Common Stock reported herein. Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. ORBIMED ADVISORS LLC /s/ Carl L. Gordon 05/15/2026 OrbiMed Capital GP X LLC /s/ Carl L. Gordon 05/15/2026