In prostate cancer, Zhang et al. have shown that at least one PD-L1-positive CTC was detected at baseline in 40% of men with metastatic hormone-sensitive prostate cancer (mHSPC), 60% of men with metastatic castration-resistant prostate cancer (mCRPC) starting abiraterone acetate/prednisone or enzalutamide (pre-ARSI), and 70% of men with mCRPC post-ARSI [17]. The gene discussed is CD274; the disease is prostate carcinoma.