TAM: tumor-associated macrophages; MDSC: myeloid-derived suppressor cells; Ref.: Reference; RNA seq: RNA sequencing; IHC: immunohistochemistry; Arg-1: arginase-1; BM: bone marrow; ROS: reactive oxygen species; TGF-β: transforming growth factor beta; GEP: gene expression profiling; MPFS: metastasis progression-free survival; IF: immunofluorescence; Fc: flow cytometry; aRMS: alveolar rhabdomyosarcoma; eRMS: embryonal rhabdomyosarcoma. Here, ARG1 is linked to alveolar rhabdomyosarcoma.