With a nine-month overall survival, Diffuse Intrinsic Pontine Glioma (DIPG) is the principal cause of non-accidental pediatric deaths. Despite many clinical trials, these patients’ outcomes have not improved in decades, pointing to the need for alternative therapies. In this sense, we have previously demonstrated that the oncolytic adenovirus Delta-24-RGD which has already shown safety and feasibility in DIPG patients, is able to recruit T cells into the tumor. However, such T-lymphocyte infiltration rapidly acquires an exhausted phenotype that prevents from achieving long-term anti-tumor responses. Therefore, we decided to improve this therapy by combining the Delta-24-RGD with the activation of the immune costimulatory receptor CD40, which is known to increase antigen presentation and enable T-cell priming. Our results showed that the combination therapy is safe and extends the survival of immunocompetent treated mice compared to single treatments or non-treated mice, resulting in 40% of complete responses. In addition, mice that rejected the tumor could control the growth of a rechallenge with the primary cells indicating the development of long-term anti-tumor immunity. We also found that the combination remodels the tumor microenvironment towards a proinflammatory scenario with increased activated dendritic cells. Such dendritic cell recruitment and the anti-tumor effect is abrogated by blocking the CSF1R receptor mainly expressed by microglia/macrophages. We believe that these results can be translational and open the door for a future innovative clinical trial.