This study is for patients with early-stage Hodgkin lymphoma, a type of cancer affecting the lymphatic system. Researchers are comparing the standard treatment, which is chemotherapy (medication used to kill cancer cells) and possibly radiation (high-energy rays to shrink tumors), with a new treatment using two drugs called brentuximab vedotin and nivolumab. These drugs are types of immunotherapy, which help the body's immune system fight cancer. Brentuximab vedotin combines an antibody, brentuximab, with a toxin, vedotin, to target and kill cancer cells. Nivolumab is a monoclonal antibody that helps the immune system attack cancer. The study aims to see if this new combination improves survival and reduces side effects compared to the standard treatment.

• The study lasts for 12 years with regular follow-ups after treatment.
• Participants will undergo various scans like PET, MRI, or CT during the trial.
• Eligibility: Ages 5-60, with specific health conditions allowed.