As shown in Figure S3C, the ETV1, CEBPD, and TBX21 marked CD4+ CTLs in MS, NFIL3, TFAP2A, and TCF7L2 marked PD‐related CD4+ CTLs, and EOMES, SPR, and HOXA10 were key TFs driving the development of CD4+ CTLs in AD. Here, CEBPD is linked to Alzheimer disease.