GZMB and cancer: To better model clinical application, we evaluated the therapeutic potential of SSRIs using a 4T1 mouse breast cancer orthotopic model (Figure S1J), which closely recapitulates the breast tumor microenvironment.61 In this model, SSRI treatment effectively suppressed tumor growth (Figure S1K) and enhanced the effector function of intratumoral CD8 T cells, as evidenced by their increased production of the key cytotoxic molecule Granzyme B (Figure S1L), further supporting the cancer therapy potential of SSRIs.