Retrospective analyses, however, have shown that PD-L1 positivity in tumor cells, as detected by immunohistochemistry, may predict improved response to anti-PD1/PD-L1 therapy in melanoma, non-small cell lung carcinoma, renal cell carcinoma, and urothelial carcinoma [8, 12, 22]. This evidence concerns the gene CD274 and non-small cell lung carcinoma.