CD274 and esophageal cancer: Recent studies have demonstrated that programmed cell death ligand 1, circulating tumour DNA, serum lactate dehydrogenase, the lymph node ratio (LNR), pathologic lymph nodes staging after neoadjuvant therapy (ypN), lymphovascular invasion, and tumour length are predictors of regression grade and long-term survival after neoadjuvant therapy in advanced oesophagus cancer.