FOXC2 and melanoma: In keeping with our observation of FOXC2-associated downregulation of Ddx58 expression and the aforementioned link between FOXC2 expression and poor PFS of melanoma patients on ipilimumab, it is worth noting that Heidegger et al. recently demonstrated the importance of tumor cell-intrinsic activation of RIG-I in the success of checkpoint blockade therapy (38).