Application of monoclonal antibodies, as potential co-inhibitors for immune checkpoints, particularly CTLA-4 and PD-1, has been utilized clinically for various malignancies, including bladder cancer, head and neck squamous cell carcinoma, Hodgkin lymphoma, non-small cell lung cancer, Merkel cell carcinoma, melanoma, microsatellite instability (MSI)-high colorectal carcinoma, and renal cell carcinoma [240]. This evidence concerns the gene CTLA4 and melanoma.