ROS1 and cancer: Cabozantinib is an inhibitor of multiple tyrosine kinases, including vascular endothelial growth factor receptor 1-3 (VEGF), hepatocyte growth factor receptor (MET), AXL, RET, KIT, FLT3, ROS1, MER, TYRO3, TRKB, and TIE-2.7 In addition, cabozantinib has immunomodulatory characteristics that neutralize cancer-induced immunosuppression.8 These characteristics possibly explain the additive clinical activity of cabozantinib with nivolumab observed in the Checkmate 9ER trial.6