BTLA and lung carcinoma: 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)).