Like CTLA‐4 blockade, therapeutic targeting of the PD‐1/PD‐L1 pathway also enhances antitumor T cell reactivity, and immune checkpoint inhibitors against both PD‐1 (nivolumab, pembrolizumab, and cemiplimab) and PD‐L1 (atezolizumab, avelumab, and durvalumab) are now standard‐of‐care therapy for many cancer types.1 Here, CTLA4 is linked to cancer.