In summary our results show that melanoma cells vary in their sensitivity to NK cell killing due to differences in expression of PD-L1, that activation of the IFNβ system leads to subsequent functional activation of the PD-L1/PD-1 immune-inhibitory signaling axis, and that melanoma cells are most sensitive to killing by NK cells in the presence of IFNβ and anti-PD-1 antibody. The gene discussed is CD274; the disease is melanoma.