Myeloid cells, including macrophages and myeloid-derived suppressor cells (MDSCs), infiltrate tumors and adopt pro-tumorigenic phenotypes that promote tumor growth and metastasis through mechanisms such as angiogenesis stimulation and immune suppression. These cells create an immunosuppressive microenvironment by inhibiting T cell function and promoting tumor immune evasion, thereby compromising the effectiveness of cancer therapies including immunotherapy, anti-angiogenic therapy, and conventional treatments. Understanding these interactions is pivotal for developing novel combination therapies that target both tumor cells and the immunosuppressive myeloid populations to enhance anti-tumor immunity and improve treatment outcomes.