The goal of this clinical trial is to explore the real-world Chinese relapsed/refractory patients to evaluate the efficacy and safety of BV monotherapy or combination therapy in CHL patients. The main questions it aims to answer are:

To evaluate the efficacy and toxicity of BV-containing regimen in relapsed/refractory CHL patients in China, and to provide reference for the rational and safe use of BV in clinical practice.

Part I: Retrospective study The clinical data of 50 cases of relapsed/refractory CHL treated with BV in multiple centers in the past 3 years were collected. Statistical methods were used to compare the efficacy and safety between groups and subgroups.

Part II: Prospective study The study was conducted in about 20 centers in China. The preliminary plan was to select a large grade A tertiary hospital with lymphoma specialty center as a sub-center, and an investigator meeting was held to further discuss the choice of drug administration and combination therapy for patients. It was initially planned that BV monotherapy would be divided into two groups: a 2-week (2W) dosing group and a 3-week (3W) dosing group. The specific dosing method was determined by the investigator, but the duration of dosing could not exceed 1 year. For the combined treatment group, it is recommended to use drugs with low neurotoxicity, such as bendamustine and gemcitabine, and dacarbazine and etoposide can also be selected. Anti-pd-1 monoclonal antibody is recommended to be administered once every 3 weeks, and sintilimab or somatorellimab can be selected. Patients who had failed previous treatment with anti-PD-1 anti-PD-1 monoclonal antibody could also be enrolled, at the discretion of the investigator. PET-CT is recommended for efficacy evaluation, and enhanced CT can also be used for patients with poor economic conditions.

Inclusion Criteria:

• Histologically, classical hodgkin lymphoma（cHL） was diagnosed and relapsed or refractory.
• Patients were treated with BV-containing regimen at least once
• Presence of tumor (measurable or nonmeasurable).
• Signature of the form consent for participation in the study.

Exclusion Criteria:

• <18 years