CTLA4 and melanoma: Recently, blocking the immune-regulatory checkpoints that limit T cell responses using antagonistic antibodies against the programmed death 1 pathway (PD-1) and one of its ligands, programmed death ligand 1 (PD-L1), and blockade of CTLA-4/B7 (cytotoxic T lymphocyte-associated antigen-4) interaction with anti-CTLA-4 antagonistic monoclonal antibodies (mAbs) have demonstrated high clinical benefits in melanoma patients [32, 33].