Fowler et al., engineered Vγ9Vδ2 γδ T cells to co-secrete GD2-specific scFv-Fc opsonin and a synthetic IL-15 fusion protein, creating an “armed” γδ T-cell platform that showed superior persistence and tumor control compared to unmodified γδ T cells in an orthotopic patient-derived osteosarcoma model (29). Here, IL15 is linked to osteosarcoma.