George RR Martin might be too busy winning Golden Globes and owning a literal railroad to write The Winds of Winter (and fair play to him, honestly), but that doesn't mean we can't get our Game of Thrones fix elsewhere. AGOT, a highly popular Game of Thrones mod for the Crusader Kings games, is finally getting its CK3 edition, so you can just yono all app author your own conclusion to the A Song of Ice and Fire story.
Although the CK2 version of mod offers a huge swathe of Westeros' history to play around in—you can start anywhere from 300 years before Aegon's Conquest right up to the beginning of the fourth book, A Feast For Crows—CK3AGOT will restrict you to starting at Robert's Rebellion for now.
You'll also only have access to the continent of Westeros itself, with Essos—the eastern continent where Daenerys spent most of her time in the TV series and all of her time in the books so far—staying as terra incognita for now. That might be a little disappointing, but it means the modders can stay within the feudal mechanics of already-existing CK3 and not have to invent a bunch of new mechanics to fit in concepts like dragons and societies like the nomadic Dothraki. All that stuff is still very much possible yono all app in future updates, too.
But even with those restrictions, there's still plenty of alternate (fictional) history fun to be had. Robert's Rebellion was an all-engulfing civil war that pretty much established Westeros as you might know it from the A Song of Ice and Fire books or the Game of Thrones TV show. Even if you can only start from there, you can still see what happens if you put Rhaegar on the Iron Throne, send Aerys Targaryen to therapy, or make Tywin Lannister be nice to his children (challenge level: impossible).
Or you can just do what PCG's Chris Livingston did in the CK2 version of the mod: Live out the epic tale of history's footnote, Lord Ninedrick of Wycliffe.
There's no download page for CK3AGOT yet, but you can keep track of the project over on its subreddit, Discord, and yono all app official forum, where the download will assuredly be posted as soon as it goes live.