For example, PD-L1 immunohistochemistry shows predictive value in NSCLC, head and neck squamous cell (HNSCC), and urothelial cancer [14–16], whereas in melanoma and RCC, PD-L1 IHC cannot be used for the prediction of ICI therapy [17, 18]. This evidence concerns the gene CD274 and head and neck squamous cell carcinoma.