Figure 2. Subgroup analysis. (A) Subgroup analysis of OS. (B) Subgroup analysis of PFS. For sex and smoking history, the HR was estimated from an unstratified Cox proportional hazards model with treatment as the fixed effect. For other variables, the HR was estimated from a Cox proportional hazards model stratified by sex (male vs female) and smoking history (≥20 pack-years vs ˂20 pack-years or never), with treatment as the fixed effect. Camre+chemo, camrelizumab plus chemotherapy; Chemo, chemotherapy; ECOG, Eastern Cooperative Oncology Group; OS, overall survival; PD-L1, programmed death-ligand 1; PFS, progression-free survival.