In a recent phase 1 trial in patients with metastatic NSCLC, the subcutaneous addition of a recombinant IL-15 agonist to the PD-1 monoclonal antibody nivolumab induced Ki-67 expression in CD8+ T and natural killer cells and increased the circulating serum levels of cytokines such as IFN-γ and IL-6 at early time points after the administration of the recombinant IL-15 agonist and nivolumab [40]. Here, PDCD1 is linked to non-small cell lung carcinoma.