C5 and paroxysmal nocturnal hemoglobinuria: In the kidney, C5 blockade has revolutionized the treatment of aHUS (Fakhouri et al., 2023; Mauch et al., 2023) and paroxysmal nocturnal hemoglobinuria (PNH) (Stern & Connell, 2019), both diseases where MAC‐mediated endothelial cell damage represents a crucial therapeutic target.