CD274 and adenocarcinoma: In the multivariate Cox analysis, PD-L1 expression (1%–49%: HR, 0.427; 95% CI, 0.225–0.811; P = 0.009; ≥50%: HR, 0.373; 95% CI, 0.176–0.793; P = 0.010), adenocarcinoma (HR, 0.589; 95% CI, 0.387–0.896; P = 0.013), and chemotherapy cycles ≥4 (HR, 0.229; 95% CI, 0.136–0.285; P = 0.001) were favorable prognostic factors for PFS.