So, I stumbled over this article from February 2018. It talks about the trust run by Michael's widow, CrichtonSun, and mentions how they're going to develop unpublished works, which we've heard before. However, at the end of the article, the writer gives a list of his novels, including the last published works, Micro and Dragon Teeth...then goes on to say, "There are two more posthumous novels set to be published by Harper Collins."
I'm not sure if this is just old information from 2009 being recycled, or if it's legit. Google searches for "Michael Crichton novel 2019 & 2020" revealed nothing, so if there are new books coming out, it's a secret for now.