A Study of Tislelizumab (BGB-A317) in Combination With Chemotherapy as First Line Treatment in Participants With Advanced Esophageal Squamous Cell Carcinoma

Key Inclusion Criteria:

1. Pathologically (histologically) confirmed diagnosis of ESCC
2. Stage IV unresectable ESCC at first diagnosis OR unresectable, locally advanced recurrent or metastatic disease (per American Joint Committee on Cancer 7th Edition), if there is prior neoadjuvant/adjuvant therapy with platinum-based chemotherapy, a treatment-free interval of at least 6 months is required.

Key Exclusion Criteria:

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.