||Innate lymphoid cells (ILCs) are recently identified lymphoid cells resident in mucosa of lung, intestine, lymphoid organs and adipose tissue. ILCs contribute to maintenance of mucosa and innate response against pathogen. Meanwhile, ILCs promote chronic inflammation in allergy model. ILCs are mainly grouped as IFNγ-producing ILC1, IL-4/13-producing ILC2 and IL-17/22-producing ILC3. Last year, progenitor cells specific to ILC lineage were found in bone marrow. However, ILC lineage commitment from these progenitor cells still remains to be elucidated. We recently showed that Runx3 is expressed in ILC1 and ILC3, and is required for their differentiation（Ebihara et al, Nat Immunol 2015）. Runx3 was a survival factor of ILC1 and regulated RORγt and AHR, both of which are required for ILC3 function and differentiation. In addition, ILC1 and ILC3 were important to control C. Rodentium infection. In this seminar, I’d like to go over recent advances in ILC research and association of NK cells with ILCs, then, focus on our recent data.