As PD-1 on CD8+ T-cell subsets is a novel identified marker in predicting the response to anti-PD-1 immunotherapies, these data suggest that SPHK1 and MTA3 may serve as potential biomarkers for the prognosis of melanoma and the efficacy of PD-1 mAb blockade therapies [53–56]. The gene discussed is CD8A; the disease is melanoma.