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. The gene discussed is CD274; the disease is non-small cell lung carcinoma.