Inclusion criteria:

   - Relapsed or refractory de novo classical Hodgkin lymphoma

   - Participant may have failed to achieve a response to, progressed after, or be
   ineligible for autologous stem cell transplant (auto-SCT)

   - Participant may have failed to achieve a response or progressed after treatment with
   brentuximab vedotin or may be brentuximab vedotin naïve

   - Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

   - Measurable disease

   - Adequate organ function

Exclusion criteria:

   - Diagnosis of immunosuppression or receiving systemic steroid therapy or any other form
   of immunosuppressive therapy within 7 days prior to the first dose of study medication

   - Prior monoclonal antibody within 4 weeks prior to study Day 1 or chemotherapy,
   targeted small molecular therapy, or radiation therapy within 2 weeks prior to study
   Day 1

   - Prior allogeneic hematopoietic stem cell transplantation

   - Known clinically active central nervous system involvement

   - Known additional malignancy that is progressing or requires active treatment

   - Has a known history of Human Immunodeficiency Virus (HIV)

   - Has known active Hepatitis B (HBV) or Hepatitis C (HCV)

   - Active autoimmune disease requiring systemic treatment in past 2 years

   - Has a history of (non-infectious) pneumonitis that required steroids, or current
   pneumonitis