Abstract Background Noninvasive prognostic biomarkers are needed for advanced non-small cell lung cancer (NSCLC) patients with different histological types to identify cases with poor survival. Here, we investigated the prognostic values of peripheral CD8+CD28+ T cells and CD8+CD28− T cells in advanced NSCLC patients treated with chemo(radio)therapy and the impact of histological type on them. Methods Of 232 registered advanced NSCLC patients, 101 treatment-naïve individuals were eligible and included in our study. Flow cytometry was used to evaluate CD8+CD28+ T cells, CD8+CD28− T cells, CD4+ CD25^hi T cells, B cells, natural killer cells, γδT cells, and natural killer T cells in patients’ peripheral blood. Results The median follow-up time was 13.6 months. Fifty-nine (58.4%) patients died by the end of our study. Fifty-three of the 101 advanced NSCLC cases selected for our study were adenocarcinomas (ADs), and 48 were squamous cell carcinomas (SCCs). Multivariate analyses showed that increased levels of CD8+CD28+ T cells independently predicted favorable overall survival (OS) [hazard ratio (HR): 0.51, 95% confidence interval (CI) 0.30–0.89, P = 0.021] and progression-free survival (PFS) (HR: 0.66, 95% CI 0.37–0.93, P = 0.038) in ADs, but the prediction in SCCs was not statistically significant. In contrast, high levels of CD8+CD28− T cells independently predicted unfavorable OS (HR: 1.41, 95% CI 1.17–3.06, P = 0.035) and PFS (HR: 2.01, 95% CI 1.06–3.85, P = 0.029) in SCCs, but the prediction in ADs was not statistically significant. ADs had higher levels of CD4+CD25^hi T cells and CD8+CD28− T cells and lower NK cells (all P < 0.05) than SCCs. Conclusions Our findings uncovered the prognostic values of peripheral CD8+CD28+ T cells and CD8+CD28− T cells in advanced NSCLC patients treated with chemo(radio)therapy, which could help to identify patients with poor outcomes and refine treatment strategies.