Brief summary

This phase III trial compares the effect of adding chemotherapy to immunotherapy (pembrolizumab) versus immunotherapy alone in treating patients with stage IIIB-IV lung cancer. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Chemotherapy drugs work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving pembrolizumab and chemotherapy may help stabilize lung cancer.