CD274 and carcinoma of esophagus: Studies have shown that when PD-L1 is used as a predictive biomarker for immunotherapy for hypopharyngeal carcinoma combined with esophageal carcinoma, the immune-related expression of tumor tissues in patients with hypopharyngeal carcinoma combined with esophageal carcinoma is significantly correlated based on PCR and immunohistochemical results7.