Currently, several PD-1 and PD-L1 antibodies are in clinical use for the treatment of various solid cancers and lymphomas, and blocking of the PD-1 pathway is able to induce impressive response rates across a broad spectrum of tumor types, like metastasized and recurrent solid tumors such as lung cancer, melanoma and gastric cancer [8–10]. Here, PDCD1 is linked to lung cancer.