Kim et al. (2019) found granulocyte/macrophage colony-stimulating factor (GM-CSF) could inhibit the differentiation of iTreg cells and GM-CSF-activated monocyte-derived DCs converted tumor-specific naive Th cells into Th9 cells, furthermore, restrained tumor growth by inducing antitumor CTLs in an IL9-dependent manner. Here, IL9 is linked to neoplasm.