Lung cancer is the leading cause of cancer mortality globally, with non-small cell lung cancer (NSCLC) accounting for 85% of cases. Despite advancements in first-line treatments such as immunotherapy and targeted therapies, resistance to these treatments is common, creating a significant unmet need for effective second-line therapies. This review evaluates current and emerging second-line therapeutic options for advanced or metastatic NSCLC, focusing on their efficacy and potential to improve patient outcomes. Anti-angiogenic drugs like ramucirumab combined with chemotherapy, particularly docetaxel, have shown moderate success. Antibody-drug conjugates (ADCs) targeting specific tumor antigens offer a promising avenue for targeted therapy, while chimeric antigen receptor (CAR)-T cell therapy and T-cell receptor therapy leverage the patient’s immune system to combat cancer more effectively. mRNA vaccines, although in early stages, show potential for inducing robust immune responses against cancer-specific antigens. Building on this foundation, recent advancements in molecular testing and the exploration of the tumor microenvironment are opening new therapeutic avenues, further enhancing the potential for personalized second-line treatments in NSCLC. While ADCs and bispecific antibodies are gaining traction, more precise biomarkers are needed to optimize treatment response. Regular monitoring through techniques like liquid biopsies allows real-time tracking of mutations such as EGFR T790M, enabling timely therapeutic adjustments. Additionally, the role of neutrophils and macrophages in the tumor microenvironment is increasingly being recognized as a potential therapeutic avenue, with Smad3 emerging as a key target. Further research into drug sequencing, toxicity management, and biomarker development remains crucial to improving NSCLC treatment outcomes.

The treatment of early-stage non-small cell lung cancer (NSCLC) is becoming increasingly complex. Standard of care management for the past decade has been adjuvant chemotherapy following curative intent resection regardless of nodal status or tumour profile. With the increased incorporation of immunotherapy in NSCLC, especially in the locally advanced, unresectable, or metastatic settings, multiple studies have sought to assess its utility in early-stage disease. While there are suboptimal responses to neoadjuvant chemotherapy alone, there is a strong rationale for the use of neoadjuvant immunotherapy in tumour downstaging, based upon the concept of enhanced T cell priming at the time of a high tumour antigen burden, and demonstrated clinically in other solid tumours, such as melanoma. In the NSCLC cancer setting, currently over 20 combinations of chemoimmunotherapy in the neoadjuvant and perioperative setting have been studied with results variable. Multiple large phase III studies have demonstrated that neoadjuvant chemoimmunotherapy combinations result in significant advances in pathological response, disease free and overall survival which has led to practice change across the world. Currently, combination immunotherapy regimens with novel agents targeting alternate immunomodulatory pathways are now being investigated. Given this, the landscape of treatment in resectable early-stage NSCLC has become increasingly complex. This review outlines the literature of neoadjuvant and perioperative immunotherapy and discusses its potential benefits and complexities and ongoing considerations into future research.