CD8⁺ T cells are well-known cytotoxic lymphoid cells that kill infected host cells or cancer cells by sensing specific antigens. To enhance the anti-tumor effect of CD8⁺ T cells, we utilized the Recombinant-Attenuated Salmonella Vaccine (RASV). In our study, we observed that RASV inoculation enhanced the anti-tumor effect mediated by CD8⁺ T cells in tumors. RASV inoculation induced hematopoiesis, which resulted in anti-tumor effects. IL-7 expression, as well as the population of common lymphoid progenitors (CLPs), increased in the bone marrow (BM) of RASV-inoculated mice. To confirm this, we analyzed the BM environment, as CLPs, which can differentiate into T cells, were increased in BM. Thus, we focused on IL-7 because it plays a crucial role in influencing CLP differentiation. IL-7 levels increased in BM cells following RASV inoculation, as IFN-γ expressed by CD4⁺ T cells stimulated BM stromal cells. This signaling pathway was associated with the IRF-1 transcription factor. Moreover, this enhancing effect was also observed in metastatic cancer models. Therefore, we suggest that IL-7, induced by RASV inoculation, contributes to the anti-tumor effect by promoting CLP differentiation.