PDCD1 and pneumonitis: As shown in Figures 5, 6, and Table 3, compared with chemotherapy, PD-1 inhibitor treated patients showed significant increase in grade 1-5 and grade 3-5 pneumonitis (RR, 4.93, 95% CI: 2.35-10.34, p < 0.001; RR, 4.19, 95% CI:1.50-11.76, p < 0.001, respectively) in NSCLS subgroup.