INCLUSION CRITERIA: Patients must have newly diagnosed histologically confirmed primary glioblastoma or gliosarcoma Patients must have undergone a gross total or near gross total resection of unifocal, confined to the supratentorial compartment tumor. Patient must have completed chemoradiation (external beam radiation with concurrent temozolomide) a maximum of 5 weeks prior to initiation of study therapy. Age greater than or equal to 18 years. Karnofsky greater than or equal to 70%  Patients must have adequate organ and marrow function as defined below:  Absolute neutrophil count greater than or equal to 1,500/mcL Platelet Count >100,000/mcL Hemoglobin > 9.0 g/dL (may be transfused to achieve this level) BUN less than or equal to 30 mg/dL Serum creatinine less than or equal to 1.7 mg/dL or creatinine clearance as measured by 24 hour urine collection as > 60 ml/min. Total bilirubin (except patients with Gilbert s Syndrome, who are eligible for the study but exempt from the total bilirubin eligibility criterion) less than or equal to 2.0 mg/dL ALT and AST less than or equal to 2.5x institutional upper limit of normal.  The effects of study treatment on the developing human fetus are unknown. For this reason, participants of reproductive potential must agree to use adequate contraception which includes a combination of TWO of the following:  Barrier method of contraception: condoms (male or female) with or without a spermicidal agent, diaphragm, or cervical cap with spermicide IUD Hormone-based contraceptive Tubal ligation  Note: Consider use in females only or both male and female participants starting from the enrollment and for the duration of study treatment and up to 6 months (women) after the last dose of the study and 6 months (men) after the last dose of the drug temozolomide. Should a woman become pregnant or  suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately.  -The patient must be able to understand and be willing to sign a written informed consent document.  EXCLUSION CRITERIA:  Definitive clinical or radiologic evidence of progressive disease. Prior placement of Gliadel wafer or local brachytherapy. Note: Tumor Treating Fields are allowed. Patients who are receiving any other investigational agents. Patients who have a history of receiving immune therapy, such as a vaccine therapy, dendritic cell vaccine or intracavitary or convectional enhanced delivery of therapy. History of allergic reactions attributed to compounds of similar chemical or biologic composition to nivolumab, ipilimumab or temozolomide. History of allergic reactions attributed to gadolinium contrast. History of severe hypersensitivity reaction to any monoclonal antibody. Prior or concurrent malignancy unless its natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen. Patients with active autoimmune disease or history of autoimmune disease that might recur, which may affect vital organ function or require immune suppressive treatment including systemic corticosteroids. These include but are not limited to patients with a history of  immune related neurologic disease, multiple sclerosis, autoimmune (demyelinating) neuropathy, Guillain-Barre syndrome or CIDP, myasthenia gravis; systemic autoimmune disease such as SLE, connective tissue diseases, scleroderma, inflammatory bowel disease  (IBD), Crohn s, ulcerative colitis, hepatitis; and patients with a history of toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome, or phospholipid syndrome. Such diseases should be excluded because of the risk of recurrence or exacerbation of disease.  Note: Patients with vitiligo, endocrine deficiencies including thyroiditis managed with replacement hormones including physiologic corticosteroids are eligible. Patients with rheumatoid arthritis and other arthropathies, Sjogren s syndrome and psoriasis controlled with topical medication and patients with positive serology, such as antinuclear antibodies (ANA), anti-thyroid antibodies should be evaluated for the presence of target organ involvement and potential need for systemic treatment but should otherwise be eligible.  -The patient must not be currently on a corticosteroid dose greater than physiologic replacement dosing defined as 30 mg of cortisone per day or its equivalent. Patients must have stopped corticosteroids above this threshold at least 7 days prior to initiation of study  treatment.  -Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations (within timeframes identified in the bullets below) that  would limit compliance with study requirements.  -Pregnant women are excluded from this study because study treatment potential for teratogenic or abortifacient effects is unknown. Because there is an unknown but potential risk for adverse events in nursing infants secondary to study treatment of the mother,  breastfeeding should be discontinued.  -Known active, chronic or history of hepatitis infection.