JAK1 and melanoma: Since IFNγ-induced PD-L1 expression is mediated through the JAK1/2-STAT1/3-IRF1 axis in melanoma cells [36], and since IRF1 appeared among the most significantly affected genes in our RNA sequencing analysis (Fig. 2B), we investigated whether this non-additive increase in PD-L1 expression was dependent on the JAK-STAT1-IRF1 pathway.