Interestingly, for headache, dizziness, and Guillain-Barré syndrome, the risk was found to be of no significance (Supplementary Figure 4A, 6A, 8A) (22, 23, 25–27, 33, 34, 36, 38, 41–44, 47, 48, 51–57), which meant that the risk trend of the aforementioned three neurological toxicities caused by PD-1/PD-L1 inhibitors was similar to that of the chemotherapy group. This evidence concerns the gene PDCD1 and Guillain-Barre syndrome.