PDCD1 and non-small cell lung carcinoma: Nowadays, immune checkpoint inhibitor (ICI) therapy against the programmed cell death-1 (PD-1) or its ligand PD-L1 axis, either alone, in the case of patients with PD-1 expression ≥ 50%, or in combination with chemotherapy, in the case of PD-1 expression < 50%, has become the standard of care in advanced NSCLC lacking driver oncogenic alterations [88].