CD274 and esophageal squamous cell carcinoma: Another meta-analysis of 2877 ESCC patients indicated high PD-L1 expression was associated with poor OS (HR = 1.38; 95% CI = 1.02–1.86; p = 0.04), especially in Asian ethnicities (HR = 1.49; 95% CI = 1.11–1.99; p = 0.008) [13], although, a more recent meta-analysis of 3677 ESCC patients showed PD-L1 expression was neither correlated with OS (HR = 1.16; 95% CI = 0.94–1.42; p = 0.16) nor DFS (HR = 0.85; 95% CI = 0.66–1.10; p = 0.21) [14].