While some drug brands are turning to celebrity endorsers to give their advertising efforts a boost, Merck has gone the other way in an advertisement for their new immuno-oncology drug, Keytruda. Meet Donna, a patient in Merck’s Keynote-024 drug trial that ultimately led to the drug’s approval. Why might celebs be more appropriate for some conditions than others? Maybe the extraordinarily personal and serious nature of a late-stage cancer diagnosis lends itself to not faking it? It’s probably smarter—and more effective—to have a real patient talking about her actual experiences with advanced non-small cell lung cancer and her treatment than, say, Tiger Woods, who once tried to convince us he drove a super ugly Buick.