ARG1 and neoplasm: A tumor promoting inflammation is driven by tumor-educated myeloid cells such as tumor-associated macrophages (TAMs) and tumor-associated neutrophils (TANs) that can produce immunosuppressive cytokines (such as arginase 1, monocyte chemoattractant protein 1, interleukin (IL) 6 and 8, and T cell inhibitory molecules (such as programmed cell death 1 (PD-1) and programmed death ligand 1 (PD-L1)) [7,8,9].