Monsters Inc came out in 2001 and made over $500 million worldwide, Monsters University, which was a prequel but essentially Monsters Inc 2, was released in 2013 and made over $700 million worldwide. Both are great movies that had very good critical response. There probably will be a 3rd installment, but I haven't heard when. It takes roughly 4 years to make an animated film and I don't think they have started since the last was in 2013 and there are no published reports of another movie. Yet. I hope they make another. As long as they have a good story it will a hit