Additional Study Information: The purpose of this study is to evaluate the combination of MEDI4736 and tremelimumab in treating non-small cell lung cancer. This study will look to see whether MEDI4736 combined with tremelimumab or MEDI4736 alone are more effective than standard of care chemotherapy in treating lung cancer and to collect information on the safety of these drugs. Both MEDI4736 and tremelimumab may help the immune system to slow down or stop tumor growth. Participants will be assigned to receive either MEDI4736 in combination with tremelimumab, MEDI4736 alone, or standard of care chemotherapy during the treatment period.