To enhance anti-cancer immunity, the inhibitors targeting these immune checkpoints, such as anti-PD-1 (nivolumab and pembrolizumab), anti-PD-L1 (atezolizumab, avelumab, and durvalumab), and anti-CTLA4 (Ipilimumab) antibodies, have been developed and are FDA-approved to treat melanoma, non-small cell lung cancer (NSCLC), bladder cancer, head and neck cancer, kidney cancer, and other cancer types [119]. The gene discussed is CTLA4; the disease is cancer.