Tumor immune microenvironment in non-small cell lung cancer progression

Non-small cell lung cancer (NSCLC), the most prevalent form of lung malignancy, remains a leading cause of cancer-related mortality despite advances in surgery, targeted therapy, and immunotherapy. A growing body of evidence implicates the tumor immune microenvironment (TIME) as a critical determinant of disease progression, immune evasion, and therapeutic resistance. This review synthesizes current insights into the roles of innate and adaptive immune populations-including tumor-associated macrophages, neutrophils, dendritic cells, mast cells, myeloid-derived suppressor cells, natural killer cells, T cells, and B cells-in shaping tumor dynamics. Special emphasis is placed on the phenotypic plasticity and functional reprogramming of these immune subsets within the TIME. We further discuss the implications of immune cell heterogeneity for immunotherapy response and resistance. By highlighting the interplay between tumor cells and the immune landscape, this review underscores the potential for TIME-informed strategies to optimize patient stratification and advance combinatorial immunotherapeutic approaches in NSCLC.