Xilio Therapeutics, Inc. is a clinical-stage biotechnology company focused on discovering and developing tumor-activated immuno-oncology therapies designed to enhance anti-cancer immune responses. The company's pipeline includes vilastobart, a tumor-activated, Fc-enhanced anti-CTLA-4 antibody being evaluated in combination with atezolizumab for advanced solid tumors and microsatellite stable metastatic colorectal cancer, and efarindodekin alfa, a tumor-activated IL-12 molecule in clinical trials for advanced solid tumors. Xilio is also advancing XTX501, a bispecific PD-1/masked IL-2 molecule, and multiple masked T cell engager programs targeting tumor-associated antigens including PSMA, CLDN18.2, and STEAP1. The company's masked immunotherapy platform aims to selectively activate immune responses within the tumor microenvironment while minimizing systemic side effects. Xilio maintains strategic collaborations with major pharmaceutical partners, including an agreement with AbbVie to develop novel tumor-activated antibody-based immunotherapies, and generates collaboration revenue to extend its development runway.