With the accumulated evidence, IL‐37 has been recognized as a typical anti‐inflammatory cytokine related to autoimmune diseases, endotoxemia, inflammatory liver injury, obesity, and cancer.8, 9, 10, 11, 12 Gao et al9 found that the intratumoral injection of IL‐37 inhibited tumor growth and the antitumor activity of IL‐37 was abrogated in mice models. Here, IL37 is linked to obesity due to melanocortin 4 receptor deficiency.