Swimmer plots showing post-nivolumab progression-free survival for the three main drugs studied according to the line of treatment in which they were received. a) Gemcitabine; b) docetaxel; c) erlotinib. Swimmer plots showing post-nivolumab progression-free survival for the three main drugs studied according to the line of treatment in which they were received. a) Gemcitabine; b) docetaxel; c) erlotinib. Adrien Costantini et al. ERJ Open Res 2018;4:00120-2017 ©2018 by European Respiratory Society