MAPT and Alzheimer disease: Some of the best‐established core biomarkers for AD include amyloid markers (Aβ42/Aβ40 levels in CSF and plasma; and amyloid PET), tau markers (p‐tau concentrations in CSF and plasma; and tau PET), and neurodegeneration markers (magnetic resonance imaging [MRI], CSF and plasma concentrations of neurofilament light chain [NfL] and brain‐derived tau).