A polymorphism in the <i>PDL1</i> gene (rs4143815) was the unique potential genetic variant of 10 year BCR (training set: <i>p</i> = 0.003, HR (95% CI) = 0.58 (0.41-0.83); replication set: <i>p</i> = 0.063, HR (95% CI) = 0.52 (0.26-1.04)) that was significantly associated with 5 year BCR (training set: <i>p</i> = 0.009, HR (95% CI) = 0.59 (0.40-0.88); replication set: <i>p</i> = 0.036, HR (95% CI) = 0.39 (0.16-0.94)).No biomarkers of OS were replicated. rs4143815-<i>PDL1</i> arose as a new immunogenetic biomarker of BCR in PCa, giving new insights into the RT/immune system interaction, which could be potentially useful in new approaches using anti-PDL1 therapies for PCa.