We discussed a potential application for treating Alzheimer’s disease (AD) by replacing microglia deficient in TREM2, which is one of the major risk factors in sporadic AD (Jonsson et al., 2013; Guerreiro et al., 2013; Yuan et al., 2016; Leyns et al., 2019; Zhong et al., 2019; Parhizkar et al., 2019; Yeh et al., 2016; Wang et al., 2015; Lambert et al., 2013), with TREM2-normal microglia (Xu et al., 2020; Zhang et al., 2023; Rao and Peng, 2023). This evidence concerns the gene TREM2 and Alzheimer disease.