Brentuximab Vedotin and Nivolumab for the Treatment of Relapsed/Refractory Classic Hodgkin Lymphoma Previously Treated With Brentuximab Vedotin or Checkpoint Inhibitors

Inclusion Criteria: * Histologically confirmed classical Hodgkin lymphoma * Patients must be 12 years of age or older * Patients must have received at least 1-2 prior multi-agent chemotherapy or immunotherapy regimens will be divided into two cohorts based on the following clinical scenarios: * Patients enrolled to cohort A must have received only ONE prior brentuximab-containing regimen with NO prior checkpoint inhibitors. Patients enrolled to cohort A must have received brentuximab as part of their first-line treatment regimen. * Patients enrolled to cohort B must have received only ONE prior immune checkpoint inhibitor- (i.e. nivolumab or pembrolizumab) containing regimen and NO prior brentuximab. Patients in cohort B may have received an immune checkpoint inhibitor during either their first- or second-line treatment regimen. * If radiation is used as part of the planned front-line treatment regimen (i.e., brentuximab vedotin-doxorubicin-vinblastine-dacarbazine \[BV-AVD\] + radiation therapy \[RT\] for bulky stage II disease), this will count as only 1 prior therapy. Additionally, radiation as consolidation after a second-line multi-agent chemotherapy regimen is permitted and will not be counted as a third regimen * No prior autologous or allogeneic transplant * Eastern Cooperative Oncology Group (ECOG) performance status =\< 2 for patients \> 18 years old, or Lansky performance status of \>= 50 for patients ages 12-18 years * Enrolling patients must have measurabl…