This study includes three treatment groups. Patients will be randomly assigned at a 2:1:1 ratio to the HLX17, US-sourced Keytruda® and EU-sourced Keytruda® group to receive the treatment of IMPs in combination with Carboplatin Plus Pemetrexed until disease progression, initiation of new anti-tumor therapy, withdrawal of informed consent form, death, unacceptable toxicity, or up to 17 cycles (whichever occurs first).