No, Plo Koon does not appear in Star Wars: The Acolyte. However, a member of his species, the Kel Dor, does appear in episode 4 as part of the Jedi expedition to Khofar.
In Star Wars canon, Plo Koon was one of the Jedi Masters that was killed by his own clone troopers during the execution of Order 66. Like so many minor or supporting characters in Star Wars ...
One of the most egregious moments of Star Wars nostalgia could be redeemed with another, more interesting character.
Nevertheless, as soon as I saw the preview of Plo Koon, the best Jedi on the Jedi ... after years of falling in love with Battle Droids with The Clone Wars show and Mr. Bones from the Aftermath ...