Xilio Therapeutics, Inc.

We maintain “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act, that are designed to ensure that information required to be disclosed in the reports that we file or submit under the Exchange Act is (1) recorded, processed, summarized and reported, within the time periods specified in the Securities and Exchange Commission’s rules and forms and (2) accumulated and communicated to our management, including our principal executive officer and principal financial officer, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure. Our management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and our management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures.

Our chief executive officer (our principal executive officer) and our chief financial and operating officer (our principal financial officer) evaluated the effectiveness of our disclosure controls and procedures as of December 31, 2025. Based upon such evaluation, our chief executive officer and chief financial and operating officer have concluded that, as of December 31, 2025, our disclosure controls and procedures were effective at the reasonable assurance level.