CTLA4 and pneumonia: PDL-1 inhibitor Atezolizumab showed significant increase in grade 1-5 pneumonitis and pneumonia (RR,6.65, 95% CI: 1.19-37.06, p < 0.001; RR,5.35, 95% CI:2.61-10.96, p < 0.001, respectively).Compared with control, there was no significant difference in grade 1-5 or grade 3-5 pneumonitis in CTLA-4 inhibitor ipilimumab subgroup.