CTLA4 and cancer: ICB therapy has revolutionized cancer immunotherapy by targeting inhibitory pathways, such as programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), which regulate immune system homeostasis under physiological conditions while tumors exploit to escape immune surveillance (74, 75).