It's coffee that is brewed using a cold immersion method in a French press.
That means hot water never touches the coffee grounds during the extraction process. Instead, the grounds steep in cold water and release flavor slowly over an extended period.
That partly depends on the beans. But this method results in low-acidity coffee with super-smooth and rich flavor. Note that cold brew is prepared as a concentrate — so you'll need to "cut" it with water or cream.
You can keep it for one week in the fridge.