CD274 and nasopharyngeal carcinoma: The ORR for PD-1 inhibitors used to treat PD-L1-positive RM-NPC patients was 31% (95%CI 26–35%), (I2 = 59.2%, P = 0.086), while the ORR for PD-L1-negative patients was 21% (95% CI 17–25%), (I2 = 0.00%, P = 0.416) (Fig. 4).