CTLA4 and neoplasm: Inhibitory checkpoint molecules produced during T-cell activation, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) that regulates the immune synapses between T cells and lymph node dendritic cells to inhibit T-cell activation, or programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) suppressing the immune synapses between T cells and tumor cells, are currently the most relevant targets for immunotherapy [15].