A recent study has shown the protective function of GzmK+CD8+T cells against neurodegenerative disease (ND), such as Alzheimer’s disease (AD), by depositing GzmK on microglia and promoting the clearance of phosphorylated Tau (pTau) protein to prevent its spread in the central nervous system (CNS) and blood [322]. This evidence concerns the gene CD8A and Alzheimer disease.