What each one is
Retail media is advertising bought on a retailer's own digital and physical properties, close to the moment of purchase. DOOH is advertising on digital screens across a network of real-world venues, not tied to a single retailer.
Where they overlap
Both reach people near decisions in the physical world. In-venue DOOH extends that reach into the many everyday places a shopper moves through beyond one store — dealerships, restaurants, gyms, offices and more — making the two complementary rather than mutually exclusive.