Delivery approaches include engineered Roseburia intestinalis (boosting tumor butyrate to 2–3 mM in CT26 models; 105), enteric-coated butyrate (3-fold gut bioavailability; 69), and TME-responsive nanoparticles (2.5-fold CD8+ T cell infiltration in MC38 tumors; 105). Here, CD8A is linked to neoplasm.