: Brain cancers represent a formidable oncological challenge characterized by their aggressive nature and resistance to conventional therapeutic interventions. The tumor microenvironment has emerged as a critical determinant of tumor progression and treatment efficacy. Within this complex ecosystem, microglia and macrophages play fundamental roles, forming intricate networks with peripheral immune cell populations, particularly T cells. The precise mechanisms underlying microglial interactions with T cells and their contributions to immunosuppression remain incompletely understood. : This review comprehensively examines the complex cellular dialogue between microglia and T cells in two prominent brain malignancies: primary glioblastoma and secondary brain metastases. : Through a comprehensive review of the current scientific literature, we explore the nuanced mechanisms through which microglial-T cell interactions modulate tumor growth and immune responses. : Our analysis seeks to unravel the cellular communication pathways that potentially underpin tumor progression, with the ultimate goal of illuminating novel therapeutic strategies for brain cancer intervention.