CTLA4 and neoplasm: ICIs achieve this by targeting inhibitory receptors and ligands on immune cells, such as programmed death protein 1 [PD-1, also named cluster of differentiation 279 (CD279)], programmed death ligand 1 (PD-L1, also named CD274), and cytotoxic T-lymphocyte associated protein 4 (CTLA-4, also named CD152), thereby blocking their interactions with ligands or receptors then alleviating tumor-induced immunosuppression [1].