TLR3 and breast cancer: Macrophage type 1‐derived extracellular vesicles were isolated and combined with PLGA nanoparticles loaded with the TLR3 agonist poly I:C as a therapeutic strategy to investigate their antitumor activity by downregulating tumor immune escape in the tumor microenvironment (TME) of breast cancer in a murine model of orthotopic tumor growth.