KRAS and neoplasm: Importantly, MDSCs and M2 tumor‐associated macrophages not only impede tumor immune surveillance but also support tumor cell proliferation via cytokine production, and could thereby foster growth of K‐RAS‐driven lung AC.38, 45 In line with these data, ruxolitinib treatment of mouse autochthonous lung tumors mainly affected the expression of pro‐tumorigenic chemokines and cytokines.