Adoptive transfer of T cells modified with chimeric antigen receptors (CAR-T cells) has changed the therapeutic landscape of hematological malignancies, particularly for acute lymphoblastic leukemia and large B cell lymphoma, where two different CAR-T products are now considered standard of care. Furthermore, intense research efforts are under way to expand the clinical application of CAR-T cell therapy for the benefit of patients suffering from other types of cancers. Nevertheless, CAR-T cell treatment is associated with toxicities such as cytokine release syndrome, which can range in severity from mild flu-like symptoms to life-threatening vasodilatory shock, and a neurological syndrome termed ICANS (immune effector cell–associated neurotoxicity syndrome), which can also range in severity from a temporary cognitive deficit lasting only a few hours to lethal cerebral edema. In this review, we provide an in-depth discussion of different types of CAR-T cell–associated toxicities, including an overview of clinical presentation and grading, pathophysiology, and treatment options. We also address future perspectives and opportunities, with a special focus on hematological malignancies.