Reproducibility of PD-L1 assessment in non-small cell lung cancer—know your limits but never stop trying to exceed them

Immunotherapy targeting the programmed death 1 (PD-1)/ programmed death-ligand 1 (PD-L1) pathway has demonstrated strong and durable anti-tumoral immune responses with significantly improved overall survival in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) (1).