In the anime in the last episode of season 3 all students fight Mirio Togata with the exception of Todoroki and Bakugo. Todoroki is asked if he isnt going to fight by Eraserhead and he says he doesnt have his temporary license and Bakugo just wasnt there. Why Bakugo didnt go with the other students to fight Mirio as training?
Bakugo was still under "house arrest" as punishment for his previous fight with Izuku which is why his only appearance in this episode is collecting everyone's rubbish as part of the punishment. As stated in the previous episode Izuku was allowed to rejoin classes early by presenting a written apology.