CD274 and neoplasm: EBV-infected tumor cells, particularly in classical Hodgkin lymphoma (cHL) and extranodal NK/T-cell lymphoma (ENKTL), often show marked overexpression of PD-L1 on their surface, driven by EBV-encoded proteins such as LMP1 and EBNA2, as well as by genetic alterations in the PD-L1/PD-L2 locus (20, 21).