PDCD1 and neoplasm: The introduction of novel therapies aimed at boosting the host immune response against the tumour by blockade of the immune checkpoint molecule programmed cell death receptor 1 (PD-1) or its cognate ligand programmed cell death ligand 1 (PD-L1) has shown durable clinical responses in first and second line setting in a subset of patients with advanced non-small cell lung cancer (NSCLC).1, 2, 3, 4, 5 Despite this, the majority of advanced NSCLC patients derive no clinical benefit from immune checkpoint blockade (ICB) targeting the PD-1/PD-L1 axis.6