Clinical trials with ICIs that target PD-1, PD-L1, and CTLA-4 have yielded exceptional results in recent years in certain types of neoplasia, which led experts at the FDA to approve the first ICI, the CTLA-4 inhibitor (Ipilimumab), in 2011 [28,29,30,31]. The gene discussed is CTLA4; the disease is neoplasm.