Next week the Cesium team will be going to the Pocono Mountains for a code sprint. See this blog post: http://cesiumjs.org/2017/05/24/Upcoming-Summer-Code-Sprint/
If there’s a particular issue or feature you’d like us to consider, just comment on it in the Cesium GitHub repo. If you are thinking of contributing, the code sprint is also a great time to open a pull request since the entire team will be active in the repo. Check out the beginner issues if you are just getting started.