Keywords: BP, bullous pemphigoid; PD-1, programmed cell death-1; PD-L1, programmed cell death ligand-1; TGF-beta; TGF-β, transforming growth factor beta; Treg, T regulatory cell; bintrafusp alfa; bullous pemphigoid; irAE, immune-related adverse events; programmed cell death ligand-1; programmed cell death receptor-1.