rHSC-DIPGVax Plus Checkpoint Blockade for the Treatment of Newly Diagnosed DIPG and DMG

Inclusion Criteria: * Subjects with newly diagnosed typical or non-typical, biopsy-proven DIPG or DMG are eligible for study enrollment. Biopsy is not required for subjects with radiographically typical DIPG meeting imaging criteria. Biopsy is required for DMG's and non-radiographically typical DIPG. Histone mutation must be confirmed by pathology report. Radiographically typical DIPG defined as a tumor with a pontine epicenter and diffuse involvement of more than 2/3 of the pons. = Subjects ages \> or = to 12 months and \< or = 18 years ("Lead In", Part A, and Part B require first three patients be \> or = to 12 years of age) * BSA \> or = 0.35m2 at the time of study enrollment * Performance score: Karnofsky \>50% of subjects \>16 years of age and Lansky \> or = 50 for subjects \< or = 16 years of age. Subjects who are unable to walk because of paralysis but are up in a wheelchair will be considered ambulatory for the purpose of assessing the performance score. * Must start radiation therapy within 42 days from date of diagnostic imaging. C1D1 must be within 42 days to 70 days post radiation (6-10 weeks). Patients CANNOT receive temozolomide during radiation * Corticosteroids should be weaned as tolerated after radiation therapy with the goal of \< or = 0.5mg/kg/day for a minimum of 7 days prior to enrollment. * Subjects must have measurable disease Exclusion Criteria: * Patients cannot receive temozolomide during radiation * Disseminated disease * Subjects who have received any cancer therapy except for radiation * Autoimmune or immune disorders * Active respiratory disorder or infection * Active viral infection