CTLA-4 blocking (anti-CTLA-4) ICIs, such as ipilimumab and tremelimumab, PD-1 blocking (anti-PD-1) ICIs, such as nivolumab and pembrolizumab, and PD-L1 blocking (anti-PD-L1) ICIs, such as atezolizumab, durvalumab, and avelumab, help T cells stay active and attack cancer cells. The gene discussed is CTLA4; the disease is cancer.