Pembrolizumab is a humanized monoclonal IgG4 antibody against PD-1, currently approved for the treatment of advanced melanoma, PD-L1-positive non-small cell lung cancer and for recurrent or metastatic head and neck squamous cell carcinoma with disease progression on or after platinum-containing chemotherapy [8]. Here, PDCD1 is linked to non-small cell lung carcinoma.