Over the past 15 years, immune checkpoint inhibitors (ICIs) targeting cytotoxic T lymphocyte-associated protein 4 (CTLA4), programmed cell death 1 (PDCD1, best known as PD-1), CD274 (best known as PD-L1) or lymphocyte activating 3 (LAG3) have been included in the standard management of an increasing number of oncological indications, de facto revolutionizing cancer care [67]. This evidence concerns the gene CTLA4 and cancer.