Additionally, weight loss may be associated with frailty and other risk factors (eg, smoking).11 In cancer, obesity is also associated with increased efficacy of programmed cell death 1 and programmed cell death ligand 1 (PD-1/PD-L1) blockade in both tumor-bearing mice and patients.12 This updated systematic review and meta-analysis was conducted to evaluate the prognosis of patients with cancer who have obesity vs those without obesity. The gene discussed is PDCD1; the disease is obesity due to melanocortin 4 receptor deficiency.