Recapitulating this clinical observation, 10 month old animal subjects, which roughly correlate to the human age of 38–47 years and engrafted with murine BSC9AJ2 melanoma cells, show decreased tumor growth as compared to 2 month old engrafted mice after treatment with anti-PD-1 mAb (Kugel et al., 2018). The gene discussed is PDCD1; the disease is melanoma.