TREM2 and obesity due to melanocortin 4 receptor deficiency: Given the importance of TREM2+ Macs in various diseases, including obesity, Alzheimer's disease, and cancer, numerous efforts are underway to pharmacologically target TREM2 signaling.[18] Our study highlights a novel possibility that harnessing the TREM2 function might have beneficial effects on the aging phenotypes of M&B units beyond the aforementioned contexts.