Tislelizumab in Participants With Relapsed or Refractory Classical Hodgkin Lymphoma

Key Inclusion Criteria: 1. Participants had a histologically confirmed diagnosis of relapsed or refractory classical Hodgkin lymphoma (cHL). 2. Participants had either: * Relapsed cHL, defined as disease progression after a partial response (PR) or complete response (CR) to their most recent therapy; or * Refractory cHL, defined as failure to achieve PR or CR to their most recent therapy. Participants were assigned to one of two cohorts based on the following: Cohort 1: Participants who were relapsed or refractory after prior autologous hematopoietic stem cell transplantation (HSCT): 1. Had failed to achieve a response or had experienced disease progression following autologous HSCT (a transplant using the participant's own stem cells). 2. Were not considered candidates for additional autologous or allogeneic HSCT (a transplant using donor stem cells). Cohort 2: Participants who were relapsed or refractory to salvage chemotherapy and had not received prior HSCT: 1. Were not considered candidates for autologous or allogeneic HSCT. 2. Had received at least one prior systemic therapy regimen for cHL. 3. Participants had measurable disease, defined as at least one positron emission tomography (PET)-positive, 2-\\\[18F\] fluoro-2-deoxy-D-glucose (FDG)-avid nodal lesion greater than 1.5 centimeters (cm) in longest diameter, or at least one FDG-avid extranodal lesion (hepatic nodule) greater than 1.0 cm in longest diameter. 4. Participants had an Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1, indicating full activity or restricted activity but capable of self-care. Key Exclusion Criteria: 1. Participants had nodular lymphocyte-predominant Hodgkin lymphoma or gray zone lymphoma. 2. Participants had received prior allogeneic HSCT. 3. Participants had received prior therapy targeting immune checkpoint pathways, including programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), programmed death-ligand 2 (PD-L2), or cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). 4. Participants had active autoimmune disease or a history of autoimmune disease with potential to relapse. Note: Additional inclusion and exclusion criteria defined in the protocol may have applied.