In the context of cancer, myeloid cells have a dual role. On one hand, they can contribute to anti-tumor immunity by recognizing and destroying cancer cells. On the other hand, certain subsets of myeloid cells, such as myeloid-derived suppressor cells (MDSCs), can promote tumor growth by suppressing the immune response and enhancing angiogenesis and metastasis. This dual nature makes them a critical focus in cancer immunology.