RecruitingPhase 2Drug trialAnti-PD-1 and CapOx for the First-line Treatment of dMMR Esophagogastric Cancer (AuspiCiOus)To investigate the effects of the combination of two chemotherapies followed by immunostimulants on the interferon gamma expression and infiltration of cytotoxic T cells in the tumour microenvironment in patients with previously untreated metastatic or locally advanced esophagogastric cancer.