This study is for people with classic Hodgkin lymphoma (a type of cancer) that did not respond to or came back after treatment. It uses two medicines: brentuximab vedotin and nivolumab. Brentuximab vedotin is a special antibody that targets and kills cancer cells. Nivolumab helps the immune system attack cancer cells. The study checks if using both medicines together works better for treating this cancer, especially in people who tried other treatments like brentuximab or checkpoint inhibitors before.

• Study Length: Treatment lasts up to 16 cycles, with each cycle being 21 days.
• Visits Needed: Treatment is given through an IV drip every 21 days.
• Follow-up: After treatment, check-ups are required for up to 5 years.

Eligible participants are 12 years or older and must meet specific health criteria, like having no major heart disease and resolving any past treatment side effects. The study will also check for safety and side effects using established guidelines. Participants must agree to take precautions to prevent pregnancy during the study.