RecruitingPhase 1Drug trialGD2 CAR T Cells in Diffuse Intrinsic Pontine Gliomas (DIPG) & Spinal Diffuse Midline Glioma(DMG)The primary purpose of this study is to test whether CAR T cells targeting GD2 (GD2CART) can be successfully made and safely given to children and adults with H3K27M-mutant diffuse midline glioma (DMG). Eligible subjects may have DMG arising in the pons (called difuse intrinisic pontine glioma, DIPG), the spinal cord, or other areas of the brain such as a thalamus