Cheng et al. identified that osteosarcoma derived exosomes induced M2 type polarization of macrophages through regulation of the expression of T cell immunoglobulin and mucin domain 3 (Tim-3) to promote the migration, invasion, epithelial mesenchymal transition (EMT), and distant metastasis of osteosarcoma cells (Cheng et al., 2021). Here, HAVCR2 is linked to osteosarcoma.