PDCD1 and cancer: Indeed, cancer cells with upregulatedPD-L1 levels are found in many cancer types, including nonsmall celllung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC),Hodgkin’s lymphoma, and renal cell carcinoma.13 Accordingly, immune checkpoint blockade (ICB) of the PD-1/PD-L1axis is an effective treatment for a number of cancers.14,15 ICB treatment usually involves the application of a PD-1 or PD-L1blocking antibody in combination with one or more other treatments,a strategy referred to as combination therapy.