A collaborative team from Mass General Brigham and Dana‑Farber reported that a single intratumoral injection of a genetically engineered oncolytic virus can remold the glioblastoma tumor microenvironment to permit deep immune cell infiltration and persistence. The intervention altered local immunobiology and increased markers associated with T‑cell activity. Investigators emphasized the virus’s capacity to overcome the immune‑excluded phenotype typical of glioblastoma, potentially enabling checkpoint inhibitors and other immunotherapies to work in a tumor type that has shown resistance to prior immune approaches. The data are preclinical/early clinical and highlight a path to combination strategies; sponsors and academic groups will need to define safety and durability in larger cohorts before pushing for late‑stage testing.