Cancer immunotherapy using anticytotoxic anti‐T‐cell antigen‐4 (CTLA4) antibodies (anti‐CTLA4) or anti‐programmed cell death‐protein1 (PD1) antibodies (anti‐PD1) have been approved for melanoma, non‐small‐cell lung cancer, and renal cell carcinoma and are also under investigation with respect to various other cancer types. The gene discussed is CTLA4; the disease is renal cell carcinoma.