Evidence from the combined inhibition of PD-1 and CTLA-4 in melanoma and NSCLC underscores the potential of combining drugs with synergistic mechanisms of action to further enhance the clinical efficacy of monotherapies, which has encouraged the ongoing development of combination therapies with ICIs, including anti-CTLA-4 antibodies and chemotherapy (65). This evidence concerns the gene CTLA4 and melanoma.