The Diablo 3 site has been updated with a schedule for end of Season 9 and subsequent start of Season 10. As always, all seasonal heroes, their stashes, Paragon levels and more will be transfered over into the non-seasonal version of the game.
Season 9 ends on March 17th. Season 10 is to start 2 weeks later, on March 31st.
You can check out what that means for seasonal characters on Diablo 3 community site.
While you're waiting for Season 10 to begin, you can take part in a special event that will yield Kanai's Skorn. The last week of March covers the date of Kevin Kanai Griffith birth. He was a D3 development team member who passed away in October 2014 from cancer. During the final week of March players will be able to meet Chief Elder Kanai and join him in a battle run that ends with a guaranteed chance of spawning a chest that contains the Kanai's Skorn transmog. The Kanai's cube and the axe from the event are in honor of Mr. Griffith.