Microsoft announced availability of Feature Pack 2 for SharePoint Server 2016, which bring us one big new feature for on-prem – SharePoint Framework!
SharePoint Framework is a page and web part model developed in SharePoint Online that allows to use modern web technologies and tools to create client-side, responsive and modern apps. With Feature Pack 2 we can create modern experiences for SharePoint Online and move them to on-prem without additional work.
SharePoint Framework for SharePoint Server 2016 includes APIs, package deployment and property panes.
It is included in September 2017 CU for SharePoint Server 2016 (it contains all feature available in Feature Pack 1).