Enzyme-triggered nanocarriers, incorporating cathepsin B-cleavable peptides, achieve site-specific activation, with quantitative assays revealing 5–10-fold higher payload delivery in protease-high tumors; for instance, hyaluronidase-degradable hyaluronic acid shells unmask targeting ligands, enhancing uptake by 3-fold in CD44-overexpressing cancers [31]. Here, CD44 is linked to cancer.