TREM2 signaling is known to be involved in many different pathologies, including neurodegenerative disease (Li & Zhang, 2018), obesity (Reich et al, 2023), and several cancers (Deczkowska et al, 2020; Katzenelenbogen et al, 2020), where it plays an important role in immunosuppression. Here, TREM2 is linked to obesity due to melanocortin 4 receptor deficiency.