摘要Osteosarcoma is a rare but deadly group of malignant tumors,including multiple subtypes and complex biological characteristics.The role of immune microenvironment of these tumors is gradually receiving attention and is considered as a key factor affecting treatment response and prognosis.This review paper aims to delve into the mechanisms of the immune microenvironment in osteosarcoma and the research progress of immunotherapy in this field.We first summarized the basic biology of the immune microenvironment of osteosarcoma,especially the role of T cells,macrophages,and other immune cells in the tumor microenvironment.Next,we reviewed the current immunotherapy strategies,including immune checkpoint inhibitors and immune cell therapy,as well as their applications and limitations in osteosarcoma.Although the immune microenvironment of osteosarcoma is complex and challenging,understanding its underlying mechanisms is expected to provide theoretical basis for developing more effective immunotherapy.