The 5th edition of the WHO Classification of Central Nervous System Tumours(WHO2021)emphasizes the importance of molecular classification. A significant update was that glioblastoma IDH-mutant from WHO2016 was renamed and classified as astrocytoma IDH-mutant WHO grade 4 in WHO2021. This review describes the current updates to the glioblastoma classification, and discusses the essential knowledge regarding daily practice, especially for young neurosurgeons.