MMP2 and urinary bladder cancer: It has been demonstrated that the expression level of MMP‐2 in breast cancer cells MDA‐MB‐231 was about sixfold higher than that in normal mammary cells HS578Bst.[117] Additionally, the expression level of HAse in high‐grade bladder cancer was about eightfold higher than that in normal bladder tissue, while the expression level of HAse showed no significant difference between low‐grade bladder cancer and normal bladder tissue.[118] Therefore, enzyme‐responsive nanomedicine has become the research hotspot in recent years and served as a promising tool to enhance the cancer immunotherapy.