PDCD1 and prostate cancer: In our review of several articles, multiple studies had shown that the prevalence of PD-L1 in patients with prostate cancer varied greatly (ranged from 0 to 92%) (Ebelt et al., 2009; Gatalica et al., 2014; Martin et al., 2015; Gevensleben et al., 2016a; Massari et al., 2016; Baas et al., 2017; Calagua et al., 2017; Ness et al., 2017; Haffner et al., 2018; Wang et al., 2018), which may account for the poor efficacy of anti-PD-1/PD-L1 immunotherapy in PCa patients in previous studies.