•Enhancing therapeutic efficacy through the exploration of combination therapies involving immune checkpoint inhibitors is of paramount importance.•Recently, our research showcased the profound impact of a combination treatment involving cordycepin and the anti-CD47 antibody on tumor growth inhibition and extended lifespan in tumor-bearing mice.•In continuation, our present study successfully devised another combination therapeutic strategy incorporating cordycepin and CTLA-4 blockade, which demonstrated a remarkable synergistic effect against cancer.•To gain deeper insights into the underlying mechanisms, we conducted single-cell RNA sequencing and flow cytometry analyses to explore the remodeling of the tumor microenvironment, providing a comprehensive understanding of the intricate changes occurring at the cellular level.•These analyses illuminated the molecular interactions and immune modulation responsible for the observed therapeutic outcomes. The strategy of using immune checkpoint inhibitors (ICIs) has revolutionized cancer treatment, leading to remarkable clinical outcomes. However, certain cancer types and patient demographics continue to face unique challenges. As a result, it is vital to investigate combination therapies that involve ICIs to boost therapeutic efficacy. Cordycepin, an adenosine derivative composed of adenine and pentose, holds immense promise for treating inflammation and cancer. Our recent research has demonstrated that the combined treatment of cordycepin and the anti-CD47 antibody significantly curtails tumor growth and extends the lifespan of tumor-bearing mice. In the current study, we showed that the combination of cordycepin and CTLA-4 blockade had a profound impact on suppressing tumor growth. We utilized the MC38 and CT26 tumor models to evaluate the therapeutic effect of cordycepin, CTLA-4 blockade, and their combined approach. Flow cytometry results unveiled that cordycepin, when combined with CTLA-4 blockade, considerably augmented the presence of tumor-infiltrating CD8+T cells and diminished the population of Foxp3+Tregs within the tumor microenvironment (TME). Additionally, we employed single-cell analysis to examine the TME’s reconfiguration upon the combined treatment of anti-CTLA-4 and cordycepin. We observed a significant impact on inhibiting tumor growth and substantially extended survival in tumor-bearing mice. Our data also demonstrated an increased proportion of effector CD8+T cells in the combined treatment group compared to all other groups, while exhausted CD8+T cells diminished in the combined group compared to the anti-CTLA-4 treatment alone. In conclusion, our findings supported the idea that combining cordycepin and CTLA-4 blockade could modify the effector and exhaustion status of CD8+T cells, thereby bolstering CD8+T-cell-mediated anti-tumor immunity in the TME. Collectively, our current study successfully established a combination therapeutic strategy utilizing cordycepin and CTLA-4 blockade. This strategy demonstrated a significant synergistic effect against cancer, highlighting its importance in cancer treatment.