This phase III trial trying to determine how safe and effective an immunotherapy drug (Tislelizumab) is as a first line treatment, in combination with chemotherapy, in patients with advanced OesophagealA Randomized, Placebo-Controlled, Double-Blind Phase 3 Study to Evaluate the Efficacy and Safety of Tislelizumab (BGB-A317) in Combination With Chemotherapy as First-Line Treatment in Patients With Unresectable, Locally Advanced Recurrent or Metastatic Esophageal Squamous Cell Carcinoma

Exclusion

1. Palliative radiation treatment for ESCC within 4 weeks of study treatment initiation
2. Prior systemic therapy for unresectable, locally advanced recurrent or metastatic ESCC
3. Received prior therapies targeting programmed cell death protein-1 (PD-1), programmed cell death protein ligand-1 (PD-L1) or PD-L2
4. Participants with evidence of fistula (either esophageal/bronchial or esophageal/aorta)
5. Uncontrollable pleural effusion, pericardial effusion, or ascites requiring frequent drainage or medical intervention (clinically significant recurrence requiring an additional intervention within 2 weeks of intervention)
6. Evidence of complete esophageal obstruction not amenable to treatment
7. Unintentional weight loss ≥ 5% within one month prior to randomization or Nutritional Risk Index (NRI) < 83.5 per investigator's choice
8. Locally advanced esophageal carcinoma that is resectable or potentially curable with radiation therapy per local investigator.
9. Participants with untreated chronic hepatitis B or chronic hepatitis B virus (HBV) carriers whose HBV DNA is ≥ 500 IU/mL or participants with active hepatitis C virus (HCV)

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.