Glioblastoma multiforme (GBM) is the most common and aggressive brain cancer in adults. It is also one of the most aggressive tumors of the central nervous system and is associated with the worst prognosis. Developing an effective treatment method is complicated by the disease: its resistance to treatment, a high recurrence rate, and genetic and histological heterogeneity. This review provides a detailed assessment of GBM diagnostic methods, molecular pathogenesis, histopathological features, and current treatment approaches. IDH mutations, together with molecular markers such as PTEN, EGFR, TP53, and MGMT promoter methylation, play a significant role in predicting the course of glioblastoma multiforme and determining treatment response. Personalized medicine and immunotherapies, together with routine treatments, represent noteworthy approaches to GBM treatment in the near future. Recent studies report that magnetic field-based interventions are a promising approach and that applications of low-frequency magnetic fields suppress glioma cell proliferation. Studies conducted with the OM-100 device have shown a significant reduction in tumor growth in both in vivo and in vitro models and have demonstrated synergistic effects when the device was combined with anti-PD-1 therapy. Furthermore, static magnetic fields have been reported to increase apoptosis, inhibit proliferation, and may offer a complementary treatment with low toxicity. These findings suggest that magnetic-field-based approaches offer an innovative strategy for GBM treatment.