CD274 and nasopharyngeal carcinoma: The current predictive capability of biomarkers, such as PD-L1 expression [18], EBV level [8], Ki67+ proliferating regulatory T cells (Tregs) [19], and tumor mutational burden (TMB) [20], has shown limited and unsatisfactory accuracy in forecasting the response to immunotherapy in NPC [14,19,21,22].