PDCD1 and non-small cell lung carcinoma: Inhibition of ‘programmed cell death 1’ (PD-1)/‘programmed cell death ligand 1’ (PD-L1) axis by nivolumab, pembrolizumab (both PD-1 inhibitors) or atezolizumab (PD-L1 inhibitor) augmented first- and second-line therapeutic options for NSCLC patients [36,37,38,39,40,41,42].