Qu (digraph)
Qu is a digraph (a pair of two letters) used in many European languages. In these languages, the letter q is special, because it almost always needs a u after it. Sometimes words have q without a u, like the French cinq, meaning five.
/k/
In many languages, like French and Spanish it is used for the /k/ sound before e and i. In English qu makes a /k/ sound in loanwords like unique and queue.
/kv/ or /kw/
In English, qu usually makes a /kw/ sound, as in quick. In German, qu makes a similar /kv/ sound.