Using TIMER2.0 online tool, we showed the correlation between NUDT21 and CAFs, Tregs, and MDSCs, and NUDT21 is positively associated with at least two cell types in multiple cancers, such as MESO, CESC, LICH, OV, PAAD, READ, SARC, SKCM, and UCEC (Supplementary Figure 2C). The gene discussed is NUDT21; the disease is cancer.