Abstract: The present invention relates to the field of prognostic of lung cancer. In this study, the inventors used extensive gene expression profiling and flow cytometry for an integrative analysis of the phenotypes of the B cells and CD4+ T cells from tumors and blood of NSCLC patients by TLS-B density. They showed that TIL B cells and TIL CD4+ T cells are more highly activated in tumors than in the periphery and that they express all the ligand/receptor pairs necessary for B/T interactions and two-way co-stimulation. Moreover, a high density of TLS-B cells is associated with higher frequencies of activated CD4+ T cells and lower frequencies of both immune checkpoint (ICP)-expressing CD4+ T cells and regulatory CD4+ T cells (Tregs) in the intratumor CD4+ T cell compartment. High densities of TLS-B cells together with low densities of FoxP3+ CD3+ Tregs in NSCLC tumors consistently identified the group of patients with the best clinical outcome.