A regulatory subpopulation of innate lymphoid cells (ILCregs) has been reported in a new study published in Cell. Distinct from ILCs and regulatory T cells, ILCregs were identified in both mouse and human intestine samples and had a unique gene identity. Using mouse models of intestinal inflammation (including a variety of inflammatory stimuli: dextran sodium sulfate, anti-CD40 antibody and Salmonella infection), the researchers found that ILCregs contributed to the resolution of innate intestinal inflammation, gradually expanding in numbers in the intestine during the process of inflammation, with peak numbers coinciding with peak inflammation levels. Moreover, ILCregs suppressed the activation of ILC1 and ILC3 subtypes via the secretion of IL-10, with autocrine transforming growth factor β1 required for the expansion and maintenance of ILCregs during inflammation.