Furthermore, microglia activation and neuroinflammation in AD are complex and heterogenous involving multiple pathways (e.g., IL6, IL‐1β, and YKL‐40) and several studies suggest that microglia activation can have adverse effects in AD (Llorens et al, 2017; Kinney et al, 2018; Gotzl et al, 2019; for review, see Butovsky & Weiner, 2018). This evidence concerns the gene CHI3L1 and Alzheimer disease.