Diffuse intrinsic pontine glioma (DIPG) is an aggressive childhood central nervous system (CNS) tumor, whose treatment is still ineffective. The immune microenvironment of DIPG is different to other CNS tumors and has hardly been studied. Immunotherapeutic approaches, such as oncolytic viruses, have emerged as promising strategies to improve the outcome of this disease. However, a remodeling of the tumor microenvironment towards a more pro-inflammatory scenario is required to potentiate their antitumor effect. Using high throughput technologies such as scRNAseq, we have studied the DIPG immune microenvironment upon treating an orthotopic DIPG mouse model with the Delta-24-ACT oncolytic adenovirus. Our study showed that the tumor microenvironment is mainly composed of myeloid cells being macrophages the most prevalent, and that further increased after Delta-24-ACT treatment. In addition, deeper characterization of macrophages phenotype uncovered Mertk as a target to modulate the activity of such population. Indeed, the inhibition of Mertk combined with Delta-24-ACT shows an increased survival rate in a DIPG orthotopic model, and an increase of the activation state and phagocytosis capacity of macrophages. In summary, even though our characterization of the DIPG immune landscape is a preliminary approach, this first overview has allowed us to discover a new targetable candidate to be combined with Delta-24-ACT for the treatment of DIPG.