CD274 and neoplasm: BBR plays also an anti-tumor role from the perspective of immunity, as it can specifically bind to glutamic acid 76 of constitutive photomorphogenic-9 signalosome 5 (CSN5) and inhibit the PD-1/PD-L1 axis through its deubiquitylation activity, leading to the PD-L1 ubiquitination and destruction (Liu et al., 2020).