Xilio Therapeutics, Inc., a biotechnology company, designs immunotherapies to improve the immune system for cancer patients. Its checkpoint inhibitor programs include XTX101, is a clinical-stage, tumor-selective anti-CTLA-4 mAb that is in Phase 1 clinical trials in patients with solid tumors; and cytokine programs comprise XTX202, XTX301, and XTX401, which are modified form of IL-2 that is masked with a protein domain to prevent binding activity until cleaved off by tumor microenvironment (TME)-associated proteases. Xilio Therapeutics, Inc. was incorporated in 2020 and is headquartered in Waltham, Massachusetts.