Nasopharyngeal carcinoma has a close association with Epstein-Barr virus (EBV).1 Plasma EBV DNA has been established as an effective marker for chemotherapy and radiotherapy.6,7,8,9,10,11 Anti–PD-1 therapy has a unique mechanism and therapeutic characteristics that are distinct from those of chemotherapy and radiotherapy.12 The value of plasma EBV DNA as a biomarker in the era of NPC immunotherapy needs to be verified. Here, PDCD1 is linked to nasopharyngeal carcinoma.