Iced Coffee is a traditional espresso based drink, brewed hot and at high pressure, in a very short time, then cool down with ice.
Cold Brew is brewed at a cold / room temperature, without pressure, with a longer extraction.
This means that the two resulting drinks have a very different sensorial profile: Cold Brew has a lower bitterness, lower acidity, it is more smooth and exalts the floral aromas present in coffee.