In our study, we show for the first time the differential expression of check-point molecules: PD-1 and CTLA-4 on CD8+ and CD4+ cells at the various stages of maturation and differentiation in the lung cancer microenviroment, e.g., bronchoalveolar lavage fluid (BALF) harvested form the tumor proximity. Here, CTLA4 is linked to lung carcinoma.