Tislelizumab Monotherapy Versus Salvage Chemotherapy for Relapsed/Refractory Classical Hodgkin Lymphoma

Key Inclusion Criteria: 1\. Histologically confirmed cHL.Must have relapsed or refractory ( cHL and 1. Has failed to achieve a response or progressed after autologous hematopoietic stem cell transplant (ASCT). or 2. Has received at least two prior lines of systemic chemotherapies for cHL and is not an ASCT candidate. 2\. Must have measurable disease 3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. 4\. Must have adequate organ functions. 5. Prior chemotherapy, radiotherapy, immunotherapy or investigational therapy used to control cancer including locoregional treatment must have been completed ≥ 4 weeks before the first dose of study drug, and all treatment-related adverse events are stable and have either returned to baseline or Grade 0/1 Key Exclusion Criteria: 1. Nodular lymphocyte-predominant Hodgkin lymphoma or gray zone lymphoma. Known central nervous system (CNS) lymphoma. 2. Prior allogeneic hematopoietic stem cell transplant. ASCT or Chimeric Antigen Receptor T-Cell Immunotherapy (CAR-T) within 100 days of first dose of study drug. 3. Prior therapies targeting PD-1 or PD-L1. 4. Prior malignancy within the past 3 years except for curatively treated basal or squamous cell skin cancer, superficial bladder cancer, or carcinoma in situ of the cervix or breast. 5. Participant with active autoimmune disease or history of autoimmune disease with high risk of recurrence. 6. Serious acute or chronic infection requiring systemic therapy. 7. Known human immunodeficiency virus (HIV), or serologic status reflecting active hepatitis B virus (HBV) or hepatitis C virus (HCV) infection. NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.