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.
The Acolyte trailer showcases new alien characters ... The most famous Kel Dor is, of course, Plo Koon. A Jedi Master by the time of the Clone Wars, Plo Koon is most notable for discovering ...