The evolving role of the immune microenvironment of tumor draining lymph nodes in the development of biomarkers of non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related mortality, and a substantial fraction of patients with resected early-stage disease experience recurrence despite curative-intent surgery. Current pathologic staging does not completely capture the biological heterogeneity that supports metastasis and drives relapse in node-negative patients. Development of robust prognostic and predictive biomarkers are needed to predict which early-stage patients are likely to progress and require additional treatment. Increasing evidence indicates that antitumor immunity is a major determinant of clinical outcome and therapeutic responsiveness. This is particularly relevant in the era of neoadjuvant, adjuvant, and perioperative immune checkpoint blockade where harnessing the potential antitumor properties of the immune system is essential. While most biomarker efforts have focused on the primary tumor alone, antitumor immune responses are orchestrated across multiple compartments, including tumor-surrounding lymph nodes, where antigen presentation, germinal center reactions including T and B cell priming and memory formation occur contributing to immunologic remodeling that can precede overt metastasis. Here, we review the cellular, transcriptional, and spatial architecture of the tumor-immune microenvironment (TIME) and lymph node immune microenvironment (LIME) in human NSCLC, emphasizing how immune cell composition, cell state, clonal dynamics, and spatial organization influence progression, recurrence risk, and response to immunomodulatory therapies. This review highlights the current technical and translational advantages and limitations of multimodal single cell technologies and discuss potential directions for early-stage NSCLC staging and optimizing therapy timing through leveraging TIME-LIME assessment utilizing multimodal technologies.