The study results of Herbst et al. 16 proved a discrepancy in PD-L1 expression between immune cells and tumour cells in several cancers, including melanoma, gastric cancer, NSCLC, renal cell carcinoma (RCC), head and neck squamous cell carcinoma (HNSCC), and pancreatic cancer. This evidence concerns the gene CD274 and hereditary clear cell renal cell carcinoma.