CTLA4 and melanoma: The development of therapies targeting immune checkpoints, for example programmed death-ligand 1 (PD-L1), programmed cell death protein 1 (PD-1) as well as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) with immune checkpoint inhibitors (ICIs) has extraordinarily changed the course of melanoma treatment, currently making possible to fight advanced melanoma with remarkably higher success.