A recent flow cytometric analysis in advanced lung cancer also supports the concept of systemic immune checkpoint expression as an association of increased numbers of PD‐L1 and PD‐L2‐positive T cells in peripheral blood with inferior survival was shown.15 This underlines the importance of considering PD‐L2 expression additional to PD‐L1 to better understand the tumorbiologic significance of PD1‐signaling. This evidence concerns the gene PDCD1LG2 and lung carcinoma.