Threonine tyrosine kinases (TTK) are often overexpressed in breast cancer cells.[59] Patients displaying high TTK levels generally have high tumor grades, usually resulting in poor clinical outcomes.[60] Inspired by a carbon‐to‐nitrogen switch from imidazo[1,2‐a]pyridazines to imidazo[1,2‐b]pyridazines in patent literature, Liu and co‐workers[31] reasoned a similar transformation for pyrazolo[1,5‐a][1,3,5]triazines would result in a more optimal PK profile as TTK inhibitors. Here, TTK is linked to breast cancer.