OS is often characterized as an immune-cold tumor with limited infiltration of anti-tumor immune cells such as CD8+ cytotoxic T cells and CD56+ NK cells, driven by potent immunosuppressive signaling from CD68+CD163+ M2 and myeloid-derived suppressor cells (MDSC) within the TME and at the tumor periphery, respectively [13,14]. Here, CD68 is linked to neoplasm.