CD274 and nasopharyngeal carcinoma: In this study, we demonstrate that (1) radiotherapy sensitizes NPC cells to NK cell killing, (2) upregulates expression of PD-1 ligand (PD-L1) in NPC cells and PD-1 receptor (PD-1) in NK cells and (3) that blocking of the PD-L1/PD-1 checkpoint further increases the killing of NPC cells by NK cells in the context of radiotherapy.