Antibodies blocking interaction between these ligands and their receptors, such as anti-CTLA4 (ipilimumab), anti-PD1 (nivolumab, pembrolizumab and pidilizumab) and anti-PD-L1, are currently used clinically with outstanding results on a proportion of patients with aggressive forms of melanoma and several advanced malignancies [81]. This evidence concerns the gene CTLA4 and melanoma.