CD8A and osteosarcoma: Research by Yahiro et al. also indicated that activation of the TLR4 signaling pathway enhances the infiltration of CD8 positive cytotoxic lymphocytes in osteosarcoma lung metastases, effectively inhibiting osteosarcoma growth and metastasis, further confirming the importance of CD8+ cells in suppressing osteosarcoma progression (Yahiro et al., 2020).