INTRODUCTION: Immunotherapy, either as monotherapy or in combination with chemotherapy, has demonstrated superior efficacy to chemotherapy alone in the frontline setting. To date, there has been no randomized study comparing immunotherapy alone with chemo-immunotherapy. AREAS COVERED: This paper reviews the immunobiological rationale for combining chemotherapy with checkpoint inhibitors as well as the data from recent phase-3 studies to understand the risks and benefits associated with either therapeutic approach for diverse patient populations. EXPERT OPINION: Frontline pembrolizumab monotherapy remains the treatment of choice for patients with high PD-L1 expression. For those with low PD-L1 expression, pembrolizumab in combination with chemotherapy can be considered.