Utilizing combined treatments of TMZ and the FDA-approved, blood–brain barrier penetrant, dual PARP1/2 inhibitor, niraparib, we found that this drug combination increased NKG2DL on GBM cells derived from multiple patient-derived xenografts (PDX) and increased the killing of GBM39 PDX derived cells by gamma delta T cells. Here, PARP1 is linked to glioblastoma.