PDCD1 and obesity due to melanocortin 4 receptor deficiency: Recent findings from a study on diet‐induced obesity in mice demonstrated an increase in exhausted CD8+ tumour‐infiltrating lymphocytes (TILs) characterized by markers such as PD‐1, TIM3 and LAG3, along with a reduction in proliferating CD8+ TILs marked by Ki67 expression [38].