Epstein-Barr Virus-Specific T Cells armed with nanobody-based B7-H3-targeting CARs could not only inhibit the growth of B7-H3+ solid tumor cells, such as colorectal cancer, non-small cell lung cancer, triple-negative breast cancer, and gastric cancer cells, but also mitigate the immunosuppressive tumor microenvironment by targeting B7-H3+ myeloid-derived suppressor cells. This evidence concerns the gene CD276 and triple-negative breast carcinoma.