Peripheral blood samples were taken from NSCLC patients before nivolumab treatment and every 6-12 weeks from the patients who continued nivolumab treatment….The plasma levels of GM-CSF and Chitinase 3-like-1 before treatment were significant correlated with PFS (P= 0.005 and P= 0.007, respectively). In addition, the changes in the plasma levels of CXCL2, VEGF, IFNa2, and MMP2 after treatment were significantly correlated with PFS (P < 0.001, P= 0.019, P= 0.014, and P= 0.010, respectively)...These six soluble factors identified in plasma can be easily measured by minimally invasive blood sampling, they could be clinically applicable as biomarkers for predicting the clinical benefit of PD-1 blocker therapy for NSCLC patients