is pepe copyrighted

I want to make an app with pepe as the main selling point. will I get in trouble?

Do a little bit of research before posting next time, while the artist technically deserves Royalty assets for anyone using this "meme" he doesn't really complain about it, and it's used everywhere, in both personal and commercial use. (EG: Youtube channels, meme websites, etc). To answer your main question, Pepe is not copywritten.