Boulenouar et al. reported that all the three T1-ILC (CD49a+ mixed ILC1, iNK cell, and mNK cell subsets) are able to preferentially kill M2 macrophages in lean conditions but have impaired cytotoxicity with obesity that may explain an increase in M2 conversion/polarization into M1 macrophages with obesity (41). The gene discussed is CCL27; the disease is obesity due to melanocortin 4 receptor deficiency.