The purpose of study is to compare the efficacy and safety of ONO-4538 in combination with carboplatin, paclitaxel, and bevacizumab (ONO-4538 group) to placebo in combination with carboplatin, paclitaxel, and bevacizumab (placebo group) in chemotherapy-naïve subjects with stage IIIB/IV or recurrent non-squamous non-small cell lung cancer unsuitable for radical radiation in a multicenter, randomized, double-blind study.