Sintilimab is a fully humanized IgG4 monoclonal antibody targeting PD-1, exhibiting a mechanism of action similar to nivolumab and pembrolizumab while demonstrating higher affinity for human PD-1.[53] Initially approved by China in 2018, sintilimab was later evaluated in the phase III ORIENT-16 trial involving patients with unresectable locally advanced or metastatic gastric and gastroesophageal junction adenocarcinoma. The gene discussed is PDCD1; the disease is gastroesophageal junction adenocarcinoma.