CD274 and gastroesophageal junction adenocarcinoma: In 2017, the US Food and Drug Administration approved pembrolizumab for the treatment of recurrent localized tumors that express PD-L1 (CPS ≥ 1) and progress after receiving 2 or more chemotherapy regimens After advanced gastroesophageal junction adenocarcinoma; pembrolizumab was approved in 2019 for recurrent, locally advanced, or metastatic esophageal cancer after first- or multiple-line systemic therapy.