The patient population included in this study had molecularly unselected metastatic castration-resistant prostate cancer without genomic evidence of tumours with a high mutational burden or microsatellite instability, a setting in which responses are expected in fewer than 10% of patients given pembrolizumab alone.3 Supporting the potential effect of immunological priming with targeted radioligand therapy, we found that clinical responders had an increase in circulating CD8 T-cell populations with a concomitant decrease in immunosuppressive myeloid cells when compared with non-responders. The gene discussed is CD8A; the disease is prostate cancer.