PDCD1 and Headache: When PD-1/PD-L1 inhibitors plus targeted therapy were compared with targeted therapy, the risk of headache of all grades was obviously higher [OR = 1.43, 95%CI:(1.09, 1.86), I2 = 0%, Z=2.62 (P = 0.0009); Supplementary Figure 4C1) (22, 23, 48).