PDCD1 and neoplasm: In the bilateral flank B16 tumor model, ZD55-IL-24 treatment in combination with PD-1 blockade significantly slowed not only local (Fig. 3b) but also distant (Fig. 3c) tumor growth compared to untreated or animals receiving isotype IgG, ZD55-IL-24 or anti-PD-1 monotherapy, or combination therapy with ZD55-IL-24 and isotype IgG.