There are several drug administration (FDA)-approved ICIs targeting PD-1, including pembrolizumab and nivolumab, as well as those targeting PD-L1, including avelumab, atezolizumab, and durvalumab for melanoma, renal cell cancer, colorectal cancer [7], head and neck cancer [8], cervical cancer [9], urothelial cancer [10], and lung cancer [11]. Here, PDCD1 is linked to melanoma.