Gene expression is regulated by a multitude of factors; however, it is likely that samples with a deletion at 9p21.3 lack expression of CDKN2A. In a pan-cancer study, Han et al. found significantly lower response rates to anti-PD-1/PD-L1 monotherapy for patients with solid tumors that harbored a 9p21 loss, including melanoma, urothelial, and NSCLC14. The gene discussed is CDKN2A; the disease is melanoma.