PDCD1 and melanoma: For instance, high expression of PD-L1 on immune cells infiltrating the tumor was shown to be an independent predictor of better melanoma patient outcomes following tumor resection [14], and a better predictor of response to PD-1 blockade than PD-L1 expression on tumor cells in immunogenic cancers such as melanoma, non-small cell lung cancer and urothelial cancer [3,4,15].