IFNG and colon carcinoma: Similar to MC38wt cells, the addition of IFN-γ to acidic culture media increased Pdl1 mRNA (Fig. 2E) and PD-L1 cell surface expression (Fig. 2F) but not total protein expression in murine CT26wt colon carcinoma cells (Fig. S4B and C) with low basal PD-L1 expression (PD-L1low, Fig. S5A-C).