Furthermore, since it is possible for drugs to be used at lower concentrations when combined and demonstrate synergistically lethal effects on cancer cells [47], it will be instructive to investigate combination treatments of CDK9 inhibitors with agents such as TMZ, BRD4 inhibitors, DNMT inhibitors, PARP inhibitors, IFN-β, and anti-PD1 in order to mitigate off-target effects while enhancing anti-tumor effects. This evidence concerns the gene CDK9 and cancer.