Recently, several studies have discovered that CD44 is of great importance to fulfilling the special properties of CSCs, such as self‐renewal and tumor microenvironment (TME) construction.[23] As mentioned above, the aberrant expression of CDK5 was dominantly enriched in CD44‐positive 4T1 cells, indicating a close link between CDK5 and CD44. Here, CDK5 is linked to neoplasm.