CD274 and esophageal squamous cell carcinoma: Several articles have analyzed that for esophageal squamous cell carcinoma (ESCC) patients with low or negative PD-L1 expression, anti-PD-L1 treatment may not provide a survival advantage (32–34), and the incidence of treatment-related adverse events and ≥Grade 3 adverse events was lower in the immune checkpoint inhibitor (ICI) group (35).