RecruitingPhase 2Drug trialA Study to Evaluate Efficacy and Safety of Tislelizumab Plus Chemotherapy for Locally Advanced Unresectable or Metastatic Gastric or Gastroesophageal Adenocarcinoma and Esophageal Squamous Cell Carcinoma in Racial and Ethnic Minority Patients in the United StatesThe purpose of this study is to characterize the clinical effects of tislelizumab, including pharmacokinetics (PK), activity, and safety assessments in US racial and ethnic minority patients with human epidermal growth factor receptor 2 (HER2)-negative, programmed death-ligand 1(PD-L1)-positive, unresectable or metastatic gastric or gastroesophageal cancer (GAC/GEA) or esophageal squamous cell carcinoma (ESCC). The study duration will be up to approximately 6 years.