PDCD1 and nasopharyngeal carcinoma: For example, while PD-L1 expression has been considered a predictive biomarker in several cancers, recent studies have shown that patients with nasopharyngeal carcinoma (NPC) can benefit from anti-PD-1 immunotherapy regardless of PD-L1 expression.3–5 Additionally, few genetic mutations are identified in NPC, indicating that TMB is not a useful predictor in this setting.6 These results highlight the unmet need for novel predictive markers for immunotherapy.