Xilio Therapeutics, Inc. is a clinical-stage biotechnology company. The Company is engaged in discovering and developing tumor-activated immuno-oncology (I-O) therapies with the goal of improving outcomes for people living with cancer without the systemic side effects of current I-O treatments. The Company is using its proprietary platform to advance a pipeline of novel, tumor-activated clinical and preclinical I-O molecules that are designed to optimize the therapeutic index by localizing anti-tumor activity within the tumor microenvironment, including tumor-activated cytokines and antibodies (including bispecifics) and immune cell engagers (including tumor-activated cell engagers and tumor-activated effector-enhanced cell engagers). Its product pipeline includes XTX101, XTX301, XTX202, XTX501, and tumor-activated bispecific molecules and immune cell engager molecules. XTX101 is an investigational tumor-activated, Fc-enhanced, high affinity binding anti-CTLA-4 monoclonal antibody.