Mix engineers today are asked to do far more than simply mix the song. In fact, it’s now expected that they clean the tracks, eliminate pops and clicks, adjust the track timing, and replace or augment some of the sounds as well. Another job that falls to many mix engineers today is correcting the pitch of any track that needs it. This process is faster and easier than ever, but like anything else, you still need good fundamental technique to seamlessly pull it off.
Some advice on pitch correction from Bobby Owsinski.