CD274 and Atypical Meningioma: Our patient’s meningioma demonstrated stable microsatellite status and PD-L1 negativity, but with a TMB of 4 Muts/Mb, which is higher than reported for atypical meningioma (mean 1.8 Muts/Mb) but lower than TMBs in other tumors (melanomas, many lung cancers, and microsatellite instability (MSI)-high cancers) (25) for which ICIs have FDA labeling.