For this, we treated GLI1-expressing human melanoma cells (WM35) either with the FDA-approved Smoothened-inhibitor vismodegib [0.5 μM] or the GLI inhibitor Hedgehog Pathway Inhibitor-1 (HPI-1) [5 μM, 10 μM] for 6 h and then added IFNγ [10 ng/mL] for another 18 h to induce STAT1 activation and IDO1 expression. Here, GLI1 is linked to melanoma.