7%), and no significant differences in the likelihood of obtaining PR were found according to sex, age, tumor histology, type of salvage chemotherapy regimen and number of prior chemotherapy regimens, indicating that patients with advanced NSCLC who have progressed following treatment with a PD-1/PD-L1 checkpoint inhibitor have a 30% better chance of achieving at least PR with salvage chemotherapy compared with those who have received prior chemotherapy but not a PD-1/PD-L1 checkpoint inhibitor. Here, PDCD1 is linked to non-small cell lung carcinoma.