CTLA4 and cancer: Metastatic castration-resistant prostate cancer, for example, shows a strong de novo resistance to CTLA4 blockade.113 In a newly developed chimeric mouse model of prostate cancer, combined treatment with PD-L1 inhibition as well as multi-kinase inhibitors cabozantinib and BEZ235, which induce a decrease in MDSC function, proved to be considerably more effective than treatment with a single agent.114 This highlights the necessity of including MDSC neutralisation in novel strategies of combined cancer treatment.