As far as the movie, Cho is shown multiple times, but only in the background or briefly mentioned by another character. He is briefly visible onscreen in the back of the group when Alby is taken by Grievers. He is also briefly seen when Ben is Banished.
His most notable appearance is when he ventures into the Maze with Thomas and some other Gladers, trying to escape. He is seen picking up his spear when Thomas is giving instructions to those with him. During the escape from the Maze, several Grievers ambush the group. One slams its tail into the ground, rupturing the ground and causing Cho to slip and fall. Another Griever grabs Cho and throws him off the edge, presumably to his death. He is the first Glader to die in the escape from the Maze.