Actually, Smad4 inhibits TGF-β-mediated conversion of ILC1-like cells from NK cells: Smad4 deficiency in NK cells does not affect ILC1 differentiation, but Smad4−/− NK cells acquire an ILC1-like gene signature and are unable to control tumor metastasis or viral infection (199). This evidence concerns the gene TGFB1 and viral infectious disease.