CD274 and neoplasm: Remarkably, we found that RT+anti-PD-L1 increased CD25+ Tregs tumor infiltration to even higher proportions compared with L19–IL2 treated groups, since IL2 promotes the proliferation of CD25+ Tregs, as CD25 (the high-affinity chain of the IL-2 receptor) is highly expressed by CD25+ Tregs.67 We also noticed the presence of a tumor-infiltrating CD25– Treg population in RT and RT+anti-PD-L1-treated groups.