Innate lymphoid cells originate from fetal liver-derived tissue-resident progenitors.

Committed progenitors with innate lymphoid cell (ILC) developmental potential are present in the fetus and bone marrow (BM). However, how fetal and BM hematopoiesis temporally and spatially contribute to ILC pools remains unclear. Here, we elucidated the distinct origins and developmental pathways of extramedullary and intramedullary ILCs in mice during ontogeny.