IO Biotech, Inc., a clinical-stage biopharmaceutical company, develops immune-modulating therapeutic cancer vaccines based on the T-win technology platform. The company's lead therapeutic cancer vaccine candidate includes IO102-IO103, which targets cancer cells and immune-suppressive cells in the tumor microenvironment that express indoleamine 2,3-dehydrogenase (IDO), and programmed death-ligand (PD-L1) that is in phase 3 clinical trial to treat melanoma, as well as in phase 2 clinical trial to treat lung, head and neck, and melanoma cancer. It also develops IO112, a product candidate that contains a single Arginase 1-derived peptide to target T cells that recognize epitopes derived from Arginase 1, which is an immunoregulatory enzyme highly expressed in difficult-to-treat tumors associated with high levels of myeloid-derived suppressor cells, including renal cell carcinoma, head and neck, breast, pancreatic, ovarian, colorectal, and prostate cancers. In addition, the company develops IO170, a TGFß1 vaccine for the treatment of solid tumors. IO Biotech, Inc. was incorporated in 2014 and is based in Copenhagen, Denmark. On March 31, 2026, IO Biotech, Inc., along with its affiliate, filed a voluntary petition for liquidation under Chapter 7 in the U.S. Bankruptcy Court for the District of Delaware.