PDCD1 and neoplasm: To escape from the control of anti-tumour immune responses elicited by vaccines, tumours have developed multiple immune-resistance mechanisms such as over-expression of ICs, including the programmed cell death-1 (PD-1)/PD-L1 axis.10,19 Blockade of this axis using anti-PD-1/PD-L1 monoclonal antibodies (mAbs) has demonstrated unprecedented clinical benefit enhancing patient outcomes and shifting the equilibrium against tumour tolerance.20,21