EEF2K and cancer: Remarkably, compound C1 exhibited potent anti‐cancer activity in the cell culture, mouse xenograft models and patient‐derived tumor organoids of TNBC, which highly express eEF2K; and the combination of C1 and paclitaxel, a commonly used chemotherapeutic drug, showed a synergistic effect against TNBC both in vitro and in vivo.