BDNF and nervous system disorder: After being internalized by different types of brain cells, NSC‐EVs promote the regenerative potential of endogenous NSCs, inhibit the excessive activation and neurotrophin production of astrocytes, rescue neuronal and synaptic damage from oxidative stress, promote remyelination capacity of oligodendrocytes, modulate inflammatory responses of resident microglia, and stimulate endothelial cell vascular regeneration, therefore ameliorating neurological disorders and accelerating post‐disease recovery.