TTF1 and lung cancer: However, considering the recent success of anti-PD-L1 antibody immunotherapy for lung cancer,17 the significance of TTF-1+PD-L1+ cells needs further investigation.24 We thus asked whether TTF-1+programmed cell death ligand 1(PD-L1)+ cells in NSCLC would correlate with the presence of the immunosuppressive IL-35+ cells.