Immune checkpoint inhibitors (ICIs), such as anti-programmed cell death 1 (PD-1) and anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4), have transformed cancer treatment, yet their efficacy in STS is variable and largely confined to undifferentiated pleomorphic sarcoma (UPS) and dedifferentiated liposarcoma (LPS). This evidence concerns the gene CTLA4 and undifferentiated pleomorphic sarcoma.