The tumor environment is greatly affected by BMI in tumoral and peritumoral adipose tissues, and it thereby influences the efficacy of immunotherapy clinically and supplies sufficient energy for cancer cells to flexibly upregulate the free fatty acid pathway, take up more lipids, and indirectly inhibit the tumor infiltration and antitumor function of CD8+ T cells (28, 29). The gene discussed is CD8A; the disease is cancer.