CTLA4 and melanoma: Antibodies that inhibit the checkpoint inhibitors, programmed death ligand 1 (PD1/PD-L1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4), have demonstrated long-term survival benefits and antitumor effects in malignancies such as renal cell carcinoma, melanoma, non-small cell lung cancer, and urothelial carcinoma [40,41,42].