NOD1/2 signaling contributes to gastro‐intestinal immunity (Philpott et al, 2014), and genetic variants in NOD2 are the strongest susceptibility factors to Crohn's disease—one of the two major inflammatory bowel diseases afflicting millions in Europe and North America alone (Hugot et al, 2001; Ogura et al, 2001; Ananthakrishnan, 2015). Here, NOD2 is linked to Crohn disease.