CDK9 and osteosarcoma: In this study, we provide evidence that the MIF inhibitor 4‐IPP has an anti‐tumour effect on osteosarcoma by promoting the degradation of the MIF protein and inhibiting the transcription of c‐Myb through hampering the formation of the downstream NF‐κB/CDK9 complex in osteosarcoma (Figure 8I).