Davidsson et al. foundthat Cutibacterium acnes contributes to an immunosuppressiveenvironment in prostate cancer by recruiting Tregs and increasing the expression ofimmunosuppressive mediators such as PD-L1 (Programmed cell death 1 ligand 1), CCL17(C-C motif chemokine ligand 17), and CCL18 (C-C motif chemokine ligand 18) (37). Here, CCL18 is linked to prostate carcinoma.