Book excerpt: Glioblastoma multiforme (GBM) is the most common and aggressive primary malignant brain tumor. Despite the efforts developed in the respective treatment, consisting of maximal surgical resection followed by adjuvant radiotherapy and chemotherapy, the prognosis remains very poor. This may be partly related to the resistance of GBM cells and their infiltrative and invasive nature into the surrounding brain tissue. Therefore, newer and challenging alternative approaches for the treatment have emerged, including immunotherapy. This anticancer therapy, based on the stimulation of the host's immune system, has been currently investigated and several advances in the clinical trial stage have already been reached. Immunotherapeutic strategies comprise a set of modalities, including vaccines (cell-free and cell-based), chimeric antigen receptor (CAR) T-cell therapy, immune checkpoint inhibitors, monoclonal antibodies (mAbs), and oncolytic viruses (OVs). In this chapter, we will review the principal concepts and the recent progress in immunotherapy for GBM.