PDCD1 and pneumonia: The pooled RRs for neutropenia, anemia, pneumonia, diarrhea, and fatigue in the MAbs targeting PD-1/PD-L1 group vs control group were 1.16 (95%CI 0.97–1.38), 1.45 (95%CI 0.89–2.36), 1.14 (95%CI 0.65–1.99), 2.98 (95%CI 0.71–12.44), and 0.40 (95%CI 0.15–1.08), respectively (Fig. 8).