CD24, also known as heat stable antigen (HSA), is a mucin-type glycosylphosphatidylinositol (GPI)-anchored glycoprotein primarily expressed on the surface of hematopoietic cells such as B lymphocytes, activated T lymphocytes, monocytes, and granulocytes, as well as certain epithelial cells. It plays a critical role in cell recognition, activation, signal transduction, proliferation, differentiation, and cell extension and movement. In the context of oncology, CD24 is highly expressed in a variety of malignant tumors, including breast, ovarian, bladder, prostate, non-small cell lung, and nasopharyngeal cancers. It has immunomodulatory functions and is involved in the interaction between tumor cells and the immune system, where it can inhibit macrophage-mediated phagocytosis of tumor cells, thereby promoting immune evasion of the tumor. Its engagement with Siglec-10 on macrophages serves as a "don't eat me" signal, which is a significant mechanism of tumor immune escape. Targeting the CD24-Siglec10 axis is an area of active research in cancer immunotherapy, as it holds potential for reprogramming the tumor immune microenvironment and enhancing anti-tumor immunity.