Microsoft is rolling out Windows 10 19H1 Build 18317 to Insiders in the Fast Ring with some major changes. This build introduces Start Menu reliability improvements, fixes critical bugs, and it also separates Cortana from Windows Search in the taskbar. Windows Search and Cortana settings have also now been split between the two, along with the familiar group policies. The public rollout of the update to production devices will kick off in April 2019, as it happened last year. The update will be finalized in March this year and the public rollout will start in April.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-19h1-update-splits-up-windows-search-and-cortana/