CTLA4 and cancer: The anti-CTLA-4 monoclonal antibody ipilimumab, anti-PD-1 monoclonal antibodies cemiplimab, nivolumab, and pembrolizumab, and anti-PD-L1 monoclonal antibodies atezolizumab, avelumab, and durvalumab overcome immune checkpoints, allowing the immune system to target cancer cells.