Inclusion Criteria:

          -  Patients must have histologically proven glioblastoma or gliosarcoma which is
             progressive or recurrent following radiation therapy and temozolomide

               -  Tumor O-6-methylguanine-deoxyribonucleic acid (DNA) methyltransferase (MGMT)
                  methylation status must be available; results of routinely used methods for MGMT
                  methylation testing (e.g. mutagenically separated polymerase chain reaction
                  [MSPCR] or quantitative polymerase chain reaction [PCR]) are acceptable

               -  Patients must have measurable contrast-enhancing disease (defined as at least 1
                  cm x 1 cm) by magnetic resonance imaging (MRI) imaging within 21 days of starting
                  treatment (patients may have gross total resection, but should have measurable
                  disease post-operatively); patients must be able to undergo MRI of the brain with
                  gadolinium; patients must be maintained on a stable corticosteroid regimen (no
                  increase for 5 days) prior to this baseline MRI

               -  Patients must be in first recurrence of glioblastoma following radiation therapy
                  and temozolomide

               -  Patients must have recovered from severe toxicity of prior therapy; an interval
                  of at least 12 weeks must have elapsed since the completion of radiation therapy
                  or placement of Gliadel wafers, and at least 6 weeks must have elapsed from the
                  last dose of temozolomide (TMZ); no prior therapies are allowed other than
                  radiation, temozolomide, and Gliadel wafers (placed during the first surgery at
                  diagnosis of GBM)

               -  Patients must have a Karnofsky performance status >= 60% (i.e. the patient must
                  be able to care for himself/herself with occasional help from others)

               -  Absolute lymphocyte count >= 1000/ul

               -  Absolute neutrophil count >= 1,500/ul

               -  Platelets >= 100,000/ul

               -  Hemoglobin >= 9 g/dl

               -  Total bilirubin =< institutional upper limit of normal

               -  Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase
                  [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase
                  [SGPT]) =< 3 x institutional upper limit of normal

               -  Creatinine =< institutional upper limit of normal OR creatinine clearance >= 60
                  ml/min/1.73m^2 for patients with creatinine levels above institutional normal

               -  Activated partial thromboplastin time (APTT) or partial thromboplastin time (PTT)
                  =< 1.5 x institutional upper limit of normal

               -  Patients must be able to provide written informed consent

               -  Women of childbearing potential must have a negative serum pregnancy test within
                  24 hours prior to treatment start; women of childbearing potential must agree to
                  use two methods of contraception (hormonal or barrier method of birth control;
                  abstinence) prior to study entry, for the duration of study treatment, and
                  through 23 weeks after the last dose of study drug; should a woman become
                  pregnant or suspect she is pregnant while participating in this study, she should
                  inform her treating physician immediately; men treated or enrolled on this
                  protocol must also agree to use adequate contraception prior to the study, for
                  the duration of study participation, and through 31 weeks after the last dose of
                  study drug

               -  Patients must have no concurrent malignancy except curatively treated basal or
                  squamous cell carcinoma of the skin or carcinoma in situ of the cervix, breast,
                  or bladder; patients with prior malignancies must be disease-free for >= five
                  years

        Exclusion Criteria:

          -  Patients receiving any other investigational agents are ineligible

               -  Patients with a history of allergic reactions attributed to compounds of similar
                  chemical or biologic composition to anti-LAG-3, anti-CD137, and anti-PD1 are
                  ineligible; the investigator brochures can be referenced for more information

               -  Patients with active or recent history of known or suspected autoimmune disease
                  are ineligible; subjects with type 1 diabetes mellitus, hypothyroidism only
                  requiring hormone replacement, and skin disorders (vitiligo, psoriasis, or
                  alopecia) not requiring systemic treatment, are permitted to enroll

               -  Patients with a condition requiring systemic treatment with either
                  corticosteroids or other immunosuppressive medications within 14 days of study
                  entry are ineligible

               -  Patients must not be receiving greater than 1 mg dexamethasone/day (or an
                  equivalent amount of an alternative corticosteroid) for at least 1 week prior to
                  treatment start

               -  Patients must have no evidence of mass effect and no midline shift

               -  Patients must have no evidence of significant hematologic, renal, or hepatic
                  dysfunction; patients with underlying hepatocellular disease should be given
                  careful risk/benefit consideration prior to enrollment; patients with a history
                  of any chronic hepatitis as evidenced by the following are ineligible:

                    -  Positive test for hepatitis B surface antigen (HBsAg)

                    -  Positive test for qualitative hepatitis C viral load (by PCR) (Note:
                       subjects with positive hepatitis C antibody and negative quantitative
                       hepatitis C by PCR are eligible; history of resolved hepatitis A virus
                       infection is not an exclusion criterion)

                    -  History of alcoholic or non-alcoholic steatohepatitis (NASH), auto-immune
                       hepatitis, or previous grade 3-4 drug-related hepatitis, or any form of
                       chronic liver disease

               -  Patients must be hepatitis C virus (HCV) negative (by quantitative PCR [qPCR])
                  and hepatitis B virus core antibody (HBcAb) negative (no prior hepatitis B
                  infection)

               -  Patients with uncontrolled intercurrent illness including, but not limited to,
                  ongoing or active infection, symptomatic congestive heart failure, clinically
                  significant cardiac disease, unstable angina pectoris, cardiac arrhythmia, or
                  psychiatric illness/social situations that would limit compliance with study
                  requirements, are ineligible

               -  Pregnant women are excluded from this study; breastfeeding should be discontinued
                  if the mother is treated with these agents

               -  Human immunodeficiency virus (HIV)-positive patients on combination
                  antiretroviral therapy are ineligible