Ligon et al. underscored the distinctive response of T cells in the metastatic osteosarcoma TME, particularly at the tumor-lung interface, where T cells, resembling TILs, manifested significant immune suppression, with increased expression of immunosuppressive markers including PD-1 and LAG-3 (Ligon et al., 2021). This evidence concerns the gene PDCD1 and osteosarcoma.