CD8A and osteosarcoma: Numerous macrophages, which can control the behavior of tumor cells, such as tumor cell migration and invasion, angiogenesis, and local immunity, invade osteosarcoma tissues.48 Therefore, the total number of macrophages is associated with osteosarcoma survival.4 T-lymphocytes are the second most infiltrating immunocyte in osteosarcoma tissues.49 In a 2015 study, Fritzsching et al50 observed improved estimated survival in patients with higher CD8+ to FOXP3+ ratios compared with survival in patients with lower ratios.