Plasmatic soluble immune checkpoints, such as programmed death protein (PD-1) with its ligands PD-L1 and PD-L2, the B7/butyrophilin-like receptors such as butyrophilin sub-family 3A (CD277) members (BTN3A) and butyrophilin sub-family 2A (CD209) members, and the B and T lymphocyte attenuator (BTLA) have been described as potential immune biomarkers in hematological malignancies (4) and solids tumors (pancreas (5), gastric (6), lung cancers (7) and hepatocarcinoma (8)). This evidence concerns the gene BTLA and lung cancer.