Mechanistically, the binding of PD-L1 with PD-1 between tumour cells and T cells promotes a pro-tumourigenic and immunosuppressive environment within tumours and reaffirms the PD-1/PD-L1 axis for immunotherapeutic targeting to modulate the immune tumour micro-environment in VS.17,34,37-40 Promisingly, there has been a single case report to date demonstrating an apparent response to immune checkpoint inhibition in VS.40 This evidence concerns the gene CD274 and neoplasm.