In 2 complementary Letters to Blood, Karschnia et al and Graham et al provide new insights into the neurological toxicities that are observed with B-cell maturation antigen–directed chimeric antigen receptor T-cell treatment for multiple myeloma, identifying a frequency of immune effector cell–associated neurotoxicity syndrome (ICANS) that exceeds 40%. Severe ICANS is identified in 8% of patients in this real-world series. Outcomes were generally favorable, although the authors describe rare, late Parkinsonism-like hypokinetic movement disorders (also known as movement and neurocognitive toxicities) post-ICANS in 2 patients.