In the univariate analysis, a PS of 2‐4, never smoking, driver mutations including those of EGFR and ALK, LDH ≥ 240 IU/L, CRP ≥ 1 mg/dL, NLR ≥ 4, liver metastasis, brain metastasis, pleural effusion, and steroid use at the commencement of nivolumab treatment were associated with a shorter PFS. The gene discussed is CRP; the disease is Pleural effusion.