Natural killer (NK) cells are innate lymphoid cells (ILCs) that participate to the clearance of pathogen‐infected cells and tumour cells. NK cells and subsets of ILCs express the natural cytotoxicity receptors (NCRs) NKp46, NKp44 and NKp30 at their surface. NCRs have been shown to recognize a broad spectrum of ligands ranging from viral‐, parasite‐ and bacterial‐derived ligands to cellular ligands; however, the full identification of NCR ligands remains to be performed and will undoubtedly contribute to a better understanding of NK cell and ILC biology.