Tamminga M, et al. - Among patients with advanced non-small cell lung cancer (NSCLC) treated with checkpoint inhibitors, researchers assessed the value of circulating tumor cells (CTC) or tumor derived extracellular vesicles (tdEV) as markers of treatment efficacy. A total of 104 patients (30 with a tumor response, 74 non-responders, 2 responses not evaluable because of early death) were included. Participants had received programmed death ligand 1 inhibitors and most of the patients took second (85%) or third line (treatment with nivolumab monotherapy (89%). Findings revealed the occurrence of CTC in one third of advanced NSCLC patients. A worse durable response rate to checkpoint inhibitors was predicted by CTC presence. Also, a link of tdEV with shorter survival but not with response was evident in this study.