We observed an interesting contradictory phenomenon that ICAM1-DXd showed a very weak cytotoxicity on CCA cell lines in vitro, whereas it mediated more potent tumor attenuation than ICAM1-MMAE in vivo, suggesting the potency of ICAM1-DXd may arise from its multifaceted biological activities instead of merely cytotoxicity. This evidence concerns the gene ICAM1 and cholangiocarcinoma.