Indeed, in the clinic, some cancer patients treated with antibodies targeting inhibitory receptors commonly known as immune checkpoint inhibitors (ICIs) including programmed cell protein death 1 (PD-1) [anti-PD-1 (pembrolizumab, nivolumab, and cemiplimab)], cytotoxic T lymphocyte antigen-4 (CTLA-4) [anti-CTLA-4 antibody (ipilimumab)], LAG3 and others (reviewed elsewhere [2]), showed improved survival associated with restored effector T-cell function and improved anticancer immunity. This evidence concerns the gene CTLA4 and cancer.