5. Expansion Phase: Initially, only immunotherapy naïve subjects who have progressed on first-line cytotoxic chemotherapy or who have declined first-line treatment with cytotoxic chemotherapy will be enrolled. Subjects with no prior systemic anti cancer therapy (i.e. first line therapy) may be enrolled in a second cohort if approved by the SMC. Subjects previously treated with systemic adjuvant therapy, other than immunotherapy for recurrent advanced NSCLC, are also eligible.