Chemokine biology on immune checkpoint–targeted therapies

The use of antagonistic immune checkpoint–targeted monoclonal antibodies has profoundly modified the standard of care and significantly increased the survival for many cancers. However, many patients still do not respond to those treatments. Biomarkers predictive for efficacy or failure of such immunotherapies would allow developing treatment stratification strategies which could further increase the survival rates of patients with cancer. Chemokines are a subset of the immune cell messenger molecules known as cytokines. Chemokines are key chemoattractant molecules which are essential for the homing of immune cells, notably within tumours. Therefore, they are good candidates for providing predictive biomarkers of the clinical response to checkpoint blockade immunotherapies. In this review, we summarise the recent advances in our understanding of the role of chemokines and how chemokine concentrations may set the tone for the efficacy of immune checkpoint–targeted immunotherapies.