In 2011, the ipilimumab, the first antibody blocking an immune checkpoint, was approved by the FDA for the treatment of melanoma, marked the beginning of the cancer immunotherapy revolution.[6] The immune responses and self‐tolerance of T cell are precisely regulated by several evolutionarily conserved T cell activating factors, such as cytotoxic T lymphocyte‐associated antigen 4 (CTLA‐4) and programmed death receptor 1 (PD‐1). The gene discussed is CTLA4; the disease is cancer.