A Study to Evaluate the Efficacy and Safety of a Sintilimab Plus ICE Regimen Versus ICE Regimen in Classic Hodgkin's Lymphoma Patients (cHL) Who Have Failed First-line Standard Chemotherapy

Inclusion Criteria: 1. Signed informed consent 2. Histopathologically confirmed cHL 3. Failed first-line standard combination chemotherapy 4. One measurable lesion (Lugano 2014) 5. Eastern Cooperative Oncology Group (ECOG) of 0-1 6. Male or female aged ≥18 years 7. Patients must have adequate organ and bone marrow function Exclusion Criteria: 1. Patients must not have known central nervous system (CNS) involvement 2. Patients must not have had prior exposure to any immune checkpoint inhibitors including anti-PD-L1 agents, anti-PD-L2 agents, or anti-CTLA-4 monoclonal antibodies 3. Patients may not simultaneously participate in another interventional clinical study 4. Patients may not receive any other investigational agents within 4 weeks of study registration 5. Patients may not receive any other form of immunosuppressive therapy within 4 weeks prior to the first dose of study drug 6. Patients may not receive live attenuated vaccines within 4 weeks prior to the first dose of study drug (or plan to receive live attenuated vaccines during the study period) 7. Patients with known immunodeficiency are ineligible 8. Patients with known active TB (Bacillus tuberculosis) are ineligible 9. Patients must not have had prior allogeneic stem cell transplantation or allogeneic organ transplantation 10. Patients must not be pregnant or breastfeeding