Number of different central nervous system manifestations in a total of 43 case reports of immune checkpoint-inhibitor (ICI)-mediated neurological adverse events (A). Measured cerebrospinal fluid (CSF) cell count (B) and protein concentrations (C) in the most common entity, encephalitis/encephalopathy. CSF cell count was analysed in 24 of 27 case reports with encephalitis/encephalopathy. CSF: cerebrospinal fluid; MS: Multiple sclerosis; NMOSD: Neuromyelitis optica spectrum disorder; PRES: Posterior reversible encephalopathy syndrome. Others*: Meningitis (2 cases), neurosarcoidosis (1 case), meningo-radiculo-neuritis (1 case), cerebral vasculitis (1 case), PML (1 case), central facial palsy (1 case), and brain lesion mimicking brain abscess (1 case).