Reply to Xiaoshuai Gao, Guo Chen, and Xin Wei's Letter to the Editor re: Keiichiro Mori, Mohammad Abufaraj, Hadi Mostafaei, et al. The Predictive Value of Programmed Death Ligand 1 in Patients with Metastatic Renal Cell Carcinoma Treated with Immune-checkpoint Inhibitors: A Systematic Review and Meta-analysis. Eur Urol 2021;79:783-92.