CTLA4 and cancer: This would imply due to the ability of syndecan‐2 peptide to reduce stromal CXCR4 and PD‐L1 expression, this gives syndecan‐2 peptide the potential to render breast tumours more susceptible to cancer immunotherapies such as α‐CTLA‐4 antibodies, tumour‐infiltrating lymphocytes (TILs) and/or chimeric‐antigen receptor T cells (CAR T cells).