Recent studies have highlighted the critical role of the tumor microenvironment in shaping immune responses in glioblastoma. Graham et al. demonstrated that meningeal lymphatics are integral to the immune response against glioblastoma, challenging the traditional view of the brain as an immune-privileged site (ref: Graham doi.org/10.1016/j.ccell.2021.02.012/). This discovery suggests that enhancing lymphatic function could improve tumor immunity. In contrast, McGrail et al. found that high tumor mutation burden (TMB-H), often considered a predictor for immune checkpoint blockade response, does not uniformly predict treatment outcomes across various cancer types, indicating that TMB alone may not be a reliable biomarker (ref: McGrail doi.org/10.1016/j.annonc.2021.02.006/). Furthermore, Pombo Antunes et al. utilized single-cell RNA sequencing to explore myeloid cell dynamics in glioblastoma, revealing that macrophage competition and specialization significantly influence tumor progression and therapeutic resistance (ref: Pombo Antunes doi.org/10.1038/s41593-020-00789-y/). Lastly, Rubio-Perez et al. characterized the immune cell profile in cerebrospinal fluid from patients with brain metastases, emphasizing the importance of immune cell infiltration in predicting responses to immune checkpoint inhibitors (ref: Rubio-Perez doi.org/10.1038/s41467-021-21789-x/). Together, these studies underscore the complexity of immune interactions within the glioblastoma microenvironment and the need for multifaceted approaches to enhance therapeutic efficacy.