The difference between iced coffee and cold brew coffee is how the coffee is brewed. Iced coffee is brewed hot and poured over ice. Cold brew coffee is brewed without heat over a longer period of time.
Cold brew coffee is usually brewed in terms of hours vs. iced coffee which is usually brewed within seconds to minutes. The way it is brewed will have a impact on the taste. Cold brew coffee is usually smoother and less bitter.