CTLA4 and cancer: The FDA has approved eleven immune checkpoint inhibitors (ICIs) for cancer therapy, including pembrolizumab, nivolumab, cemiplimab, dostarlimab, and retifanlimab (targeting PD-1); atezolizumab, durvalumab, and avelumab (targeting PD-L1); ipilimumab and tremelimumab (targeting CTLA-4); and relatlimab (targeting LAG-3) [145,146,147,148].