As soon as they have something new to announce I think we will hear from them, but not until then and I think that they do not have much to show right now. They are probably working on the legacy edition and their planned content for 2019 and 2020.
What has happened with Battlefield 5 and Anthem which both belong to EA could be a reason for the silence as well. It is possible that they are restructuring and moving people. I do not think this will affect Maxis a lot though but if they are making a new game, this is probably a good time to move people around. It is the end of the fiscal year for EA, so it is possible that they simply do not know how much money they will get to make content for the sims4.