Cascara, known also as coffee cherry tea, is fairly new to most people in the United States, but it has been served in Yemen and Ethiopia for a long time, according to Brenna Ciummo at Fresh Cup Magazine. It's made when the coffee beans are removed from the husks and the husks are dried in the sun.
Take a look at the video below to see the coffee beans being separated from the husk. These husks often get composted or are disposed of in other ways, but by making cascara tea from them, less of the coffee plant is wasted.
Cascara can't be categorized as coffee since it's not made from the bean and doesn't taste like coffee. It also isn't actually a tea because it's made from the coffee plant and is made from a fruit. Ciummo says it's best categorized as a fruit tisane, or herbal tea. It is slightly sweet and has fruit notes to it. The drink does contain caffeine, but only about a quarter of the amount that coffee does.
Because cascara is brewed like tea, it can be made hot or cold, using whatever method you prefer to make tea. Here are two variations on making cascara.
If you have a Chemex, you can make coffee cherry tea this way. I imagine you would be able to use the same method using a French press.
If all you have is a teapot, you can make cascara tea directly in it.
One different way to use cascara tea is to use the dried husks to make a simple syrup, and use the cascara syrup in a rum-based cocktail named Sun Streaks in the Coffeelands.