CD8A and neoplasm: Examining the relationship between NNMT expression and immune cell infiltration levels in the tumor microenvironment, we observed a significant positive correlation between NNMT expression and infiltration of six immune cell types (B cells, CD8 + T cells, CD4 + T cells, macrophages, neutrophils, and dendritic cells) in COAD, READ, KIRP, SKCM-M, OV, KIRC, LUSC, and SARC (Fig. 5A).