In this study, we investigated the effect of anti-PD-1 ICB therapy, or RIT, using the humanized anti-melanin mAb h8C3 conjugated to either 177Lu or 225Ac, or a combination of these therapies, on tumor growth and survival in the Cloudman S91 murine melanoma in the immune-intact DBA/2 (DBA/2NCrl) mouse model. The gene discussed is PDCD1; the disease is neoplasm.