黑咖啡will do :) But in some places, you might need to say美式咖啡 (American Coffee / Americano) to get a cup of black coffee, because 黑咖啡(Black coffee) is coffee without sugar and milk, and 美式咖啡(American Coffee / Americano) is 義式濃縮咖啡(Espresso) with a lot of water(also without sugar and milk).

黑咖啡 is right.

Yes we just simply say 黑咖啡. 原味咖啡 or 纯咖啡, etc, are kinda weirdd

просто 咖啡

black coffee is the coffee without sugar and milk, so you cannot just translate it based on the meaning of each word. The correct translation should be "原味咖啡", or "纯咖啡".