PDCD1 and lung cancer: In 1st line (HR 0.84, 95% CI 0.6-1.02, p = 0.07, Fig. 8a), “≥2nd line” (HR 0.94, 95% CI 0.88-1.01, p = 0.11, Fig. 8b), anti-PD-1 (control group ) (HR 0.92, 95% CI 0.84-1.02, p = 0.21, Fig. 8c), anti-PD-L1 (control group) (HR 0.99, 95% CI 0.90-1.09, p = 0.83, Fig. 8d), melanoma (HR 0.74 , 95% CI 0.61-0.90, p = 0.003, Fig. 8f), lung cancer (HR 0.96, 95% CI 0.87-1.05, p = 0.34, Fig. 8g) and head and neck squamous cell carcinoma (HR 0.93, 95% CI 0.82-1.05, p = 0.25, Fig. 8h) groups, there was no significant difference in OS between ICI combination therapy and ICI monotherapy.