• Written informed consent and HIPAA authorization for release of personal health information. NOTE: HIPAA authorization may be included in the informed consent or obtained separately.

• Age ≥ 18 years at the time of consent.

• ECOG Performance Status of 0, 1 or 2.

• Histologically confirmed diagnosis of classical Hodgkin lymphoma that is relapsed or refractory - historical biopsy at last relapse is acceptable. NOTE: a repeat biopsy is not required for Phase I if the historical biopsy was performed at the most recent relapse, without remission in between. A fresh biopsy is not required for Phase II.

• Presence of radiographically measurable disease (defined as the presence one or more ≥ 1.5 cm lesions, as measured in the longest dimension by PET/CT) within 4 weeks of study registration.

• Prior therapy with check-point inhibitors (nivolumab, pembrolizumab, others) and subsequent progressive disease, stable disease or mixed response

• Failed at least 2 prior therapies including cytotoxic chemotherapy including ABVD or similar, autologous transplantation, brentuximab vedotin, allogenic transplantation without active graft versus host disease Note: Patients who are eligible and willing to undergo autologous transplant should not be enrolled on this trial

• Prior cancer treatment must be completed at least 14 days prior to registration and the patient must have recovered from all reversible acute toxic effects of the regimen (other than alopecia) to ≤Grade 1 or baseline. Radiation therapy must be completed at least 7 days prior to registration.

• Absolute Neutrophil Count ≥ 1000/μL

• Platelets ≥ 75,000/μL (or ≥50,000/mm3 if known BM involvement)

• Calculated creatinine clearance ≥ 40 cc/min using the Cockcroft-Gault formula

• Bilirubin ≤ 1.5 x upper limit of normal (ULN)

• Aspartate aminotransferase (AST) ≤ 2.5 × ULN

• Alanine aminotransferase (ALT) ≤ 2.5 × ULN

• Females of childbearing potential must have a negative serum pregnancy test within 7 days prior to registration. NOTE: Females are considered of child bearing potential unless they are surgically sterile (have undergone a hysterectomy, bilateral tubal ligation, or bilateral oophorectomy) or they are naturally postmenopausal for at least 12 consecutive months

• Males who are sexually active with partners of child-bearing potential must be willing to abstain from heterosexual activity or adhere to contraception from the time of written consent until 7 months after treatment discontinuation.

• Patient must provide voluntary written informed consent prior to the performance of any research related tests or procedures.