PDCD1 and non-small cell lung carcinoma: Patients manifesting a pronounced PD-L1 expression profile exhibit greater efficacy to treatment with ICI [70].PD-L1 protein levels in NSCLC unveil intra-tumoral heterogeneity and substantial inter assay variability or discordance [71].The presence of a reservoir of PD-1-negative effector T lymphocytes establishes an immune-privileged microenvironment that exerts a beneficial influence on patient survival [49].