CTLA4 and melanoma: By interfering with these inhibitory signals, checkpoint mAbs enhance the immune system's defenses against cancer cells.73 Several immune checkpoints have been identified, with cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) being the most thoroughly investigated and recognized for their role in immune checkpoint blockade (ICB).74,75 For example, following the approval of Ipilimumab, a CTLA-4 inhibitor, for treating melanoma, patient survival rates significantly improved.76Table 3 summarizes the key points regarding the types of antibodies.