The first study evaluated the PD-1 inhibitor nivolumab for patients with early stage NSCLC and preliminary results presented at the 2017 ASCO Meeting showed that 43% of treated patients displayed a major pathological response, correlating with tumor mutation burden pre-treatment and associated with the influx of PD-1+ CD8+ T lymphocytes into responding tumors [304]. Here, PDCD1 is linked to non-small cell lung carcinoma.