CD40 and cancer: We also demonstrated that co-stimulation provided by MyD88 and CD40 (MC domain) enabled the Co-STAR-1 and Co-STAR-2 T cells to eradicate cancer cells in mice displaying on average 1–2 pHLAs per cell, which far exceeds the lower antigen density limits previously studied in vitro or in vivo with TCR-like CARs (summarized in table S3).