Notably, obesity induces T-cell depletion, as evidenced by increased expression of PD-1, T cell immunoglobulin and mucin domain-3 (TIM-3), and lymphocyte activation gene-3 (LAG-3) in tumor-bearing mice with diet-induced obesity (DIO) (8, 32). This evidence concerns the gene PDCD1 and obesity due to melanocortin 4 receptor deficiency.