CD73 (Ecto-5‘-Nucleotidase): This cell surface enzyme catalyzes the conversion of extracellular AMP into adenosine. High concentrations of adenosine in the tumor microenvironment bind to A2A receptors on immune cells, delivering a potent immunosuppressive signal that inhibits T cell and NK cell function while promoting the activity of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs). Transforming Growth Factor-Beta (TGF-β): This pleiotropic cytokine is often overproduced in tumors and plays a dual role in cancer progression. In the immune context, TGF-β suppresses the activity of cytotoxic T cells and NK cells, promotes the differentiation and function of Tregs, and drives the epithelial-to-mesenchymal transition (EMT), which facilitates metastasis.