Glioblastoma (GBM) is the most aggressive primary brain tumor. Combination therapy with surgery, radiation, and chemotherapy is not curative at present and carries a significant risk of toxicity. Advancements in the knowledge of tumor biology and tumor microenvironment have led to the development of novel targeted therapies for glioblastoma. In the past 15 years, a vast amount of pre-clinical data has been generated for glioblastoma immunotherapy. Translating these promising results into the clinic is, however, still an evolving process. Early clinical trials have demonstrated the feasibility and safety of several such approaches in patients with recurrent as well as newly diagnosed glioblastoma. Both passive as well as active immunotherapeutic modalities have also shown potential clinical benefit in at least a subset of these patients. This brief review discusses 'why' and 'how' various types of immunotherapies are being employed to treat glioblastoma.