Objective:The tumorigenesis, progression, and metastasis of lung cancer are mostly governed by the immunosuppres-sive profile. This study aimed to explore the levels of various immunosuppressive inhibitory molecules in lung-cancer patients subject-ed to different chemotherapy cycles. Methods:Thirty-three patients with advanced lung cancer (ALC;stages III-IV) without receiving prior chemotherapy and 23 healthy subjects were enrolled in our study. Peripheral blood samples were collected from the patients be-fore each chemotherapy cycle. The inhibitory markers expressed in T cells such as TIM3, PD-1, and CTLA4 were analyzed by flow cy-tometry. Results:The percentages of CD4+TIM3+, CD8+TIM3+, CD4+PD-1+, CD8+PD-1+, CD4+CTLA-4+, and CD8+CTLA-4+T cells in the peripheral blood of the ALC patients were significantly higher compared to the controls. The percentage of CD4+TIM3+, CD8+TIM3+, CD4+PD-1+, and CD8+PD-1+T lymphocytes in the peripheral blood of patients (n=19) who achieved PR or SD significantly de-creased after five cycles of chemotherapy (P<0.05). Similarly, the percentages of CD4+CTLA-4+and CD8+CTLA-4+T cells in the pa-tients also decreased after five cycles of treatment. Conclusion:The immune status of ALC patients was evidently suppressed. Effec-tive chemotherapy successfully potentiated effective immune responses by downregulating inhibitory molecules in T cells.