CD4 and neoplasm: Here, we show that intratumoral treatment with IL-15 complexes, when combined with anti-PD-1 therapy, significantly enhances the expression level of CD8+ T cell-related genes relative to those of CD4+ TREG cells in the TME compared to the CD8+ T cell: CD4+ TREG ratio in tumor-bearing mice treated with anti-PD-1 therapy and control (PBS/IgG isotype) treatment (Figure 2J).