This Starbucks is located inside the lobby of the Key Center - directly adjacent to the Cleveland Marriott Downtown. You go down a short hallway from the hotel, through a set of doors and the Starbucks is on your right.
Some times the line here can be long - but there were a lot of staff working and the line went fast. Had a triple shot iced latte with whole milk. Strong, tasty and delicious! Just what my brain cells ordered!