Inclusion Criteria:

          -  Histologically confirmed World Health Organization Grade IV glioblastoma with
             supratentorial distribution.

          -  Unequivocal evidence of progressive disease on contrast-enhanced brain CT or MRI as
             defined by RANO criteria, or documented recurrent glioblastoma on biopsy.

          -  Prior therapies including radiation and temozolomide.

          -  Only 1-2 prior treatments for recurrences are allowed. Resection of recurrent
             glioblastoma is not considered a prior treatment.

          -  Must be at least 12 weeks from radiotherapy or progression outside of the high-dose
             radiation target volume or unequivocal evidence of progressive tumor on biopsy.

          -  All adverse events Grade > 1 related to prior therapies (chemotherapy, radiotherapy,
             and/or surgery) must be resolved, except for alopecia.

          -  Karnofsky Performance Status (KPS) ≥ 60

          -  Adequate organ and marrow function as defined below, all screening labs should be
             performed within 14 days of treatment initiation:

               -  absolute neutrophil count ≥ 1,000/mcL

               -  platelets ≥ 100,000/mcL

               -  hemoglobin > 8.0 mg/dL

               -  total bilirubin ≤ 2.0 x upper limit of normal

               -  AST (SGOT)/ALT (SGPT) ≤2.5 × upper limit of normal

               -  creatinine or creatinine clearance ≥60 mL/min/1.73 m2 for creatinine >ULN

          -  Corticosteroid dose must be stable or decreasing for at least 5 days prior to
             enrollment.

          -  Ability to understand and the willingness to provide written informed consent.

        Exclusion Criteria:

          -  Infratentorial disease.

          -  Prior use of bevacizumab, ipilimumab or other CTLA-4 inhibitor, or TTFields.

          -  Tumors with known IDH1 or IDH2 mutations.

          -  History of allergic reactions attributed to compounds of similar chemical or biologic
             composition to nivolumab or ipilimumab or their excipients.

          -  Current or planned participation in a study of an investigational agent or using an
             investigational device.

          -  Uncontrolled intercurrent illness that would limit compliance with study requirements.

          -  Active or life-threatening infection requiring intravenous or >2 weeks of systemic
             therapy.

          -  Prior stereotactic radiotherapy, convection enhanced delivery (CED) or brachytherapy
             requires a biopsy to confirm radiographic progression is consistent with progressive
             tumor and not treatment-related necrosis unless the recurrent lesion is outside of any
             prior high-dose radiation target volume or distant from the prior CED or brachytherapy
             site.

          -  breastfeeding must be discontinued by enrollment on study.

          -  Uncontrolled HIV or AIDS is not allowed. Patients with known history of HIV but with
             undetectable viral load on antiretroviral therapy are allowed.

          -  CHF, or MI or hemorrhagic/ischemic stroke in the last 3 months.

          -  Active illicit drug use or diagnosis of alcoholism

          -  Known additional malignancy that is progressing or requires active treatment within 3
             years of start of study drug.

          -  Any surgery (not including minor diagnostic procedures such as lymph node biopsy)
             within 2 weeks of start of treatment.

          -  Any significant autoimmune disorders expected to impact multiple or internal organs,
             excluding mild eczema or autoimmune thyroiditis treated with thyroidectomy and
             requiring systemic immunosuppressive or immunomodulatory therapy.

          -  Any implanted programmable cranial device, including reprogrammable
             ventriculoperitoneal shunt (VPS) or cochlear implants, that precludes use of TTFields
             (Optune) therapy.