ARG1 and neoplasm: found that the nanocomposites of ferumoxytol (FMT) and TLR3 agonist poly (I : C) (PIC) (denoted as FP‐NPs) could attenuate melanoma progression and lung metastasis by promoting NF‐κB signaling‐mediated M1‐polarization, which decreased M2 related CD206, Arg1 markers and increased M1‐related CD86, iNOS, TNF‐α markers, as well as, NO generation.[117] In addition, the FP‐NPs could augment tumor‐phagocytosis of macrophages via NOX2‐derived ROS production.