Distinct cellular mechanisms underlie chemotherapies and PD-L1 blockade combinations in triple-negative breast cancer

T follicular helper (Tfh) cells. Nab-paclitaxel, unlike PTX, also reshapes the myeloid compartment, expanding mast cells and pro-inflammatory macrophages. Our analyses in human TNBC and murine models underscore the crucial role of mast cells in orchestrating anti-tumor immune responses, likely by promoting the recruitment and activation of T and B cells. In vivo experiments demonstrate that activating mast cells alongside PD-L1 blockade attenuates TNBC progression, suggesting mast cells as a promising adjunct for enhancing ICB therapy efficacy.