The last update we got from Martin was:
"I’ve been so slow with these books," Martin told Rolling Stone. "The major points of the ending will be things I told [Benioff and Weiss] five or six years ago. But there may also be changes, and there’ll be a lot added." - mentalfloss
Also, form notablog (official communication from George R.R. Martin)
How will it all end? I hear people asking. The same ending as the show? Different?
Well… yes. And no. And yes. And no. And yes. And no. And
I am working in a very different medium than David and Dan, never
forget. They had six hours for this final season. I expect these
last two books of mine will fill 3000 manuscript pages between them
before I’m done… and if more pages and chapters and scenes are needed,
I’ll add them. And of course the butterfly effect will be at work as
well; those of you who follow this Not A Blog will know that I’ve been
talking about that since season one. There are characters who never
made it onto the screen at all, and others who died in the show but
still live in the books… so if nothing else, the readers will learn
what happened to Jeyne Poole, Lady Stoneheart, Penny and her pig,
Skahaz Shavepate, Arianne Martell, Darkstar, Victarion Greyjoy, Ser
Garlan the Gallant, Aegon VI, and a myriad of other characters both
great and small that viewers of the show never had the chance to meet.
And yes, there will be unicorns… of a sort…
So the answer is yes and no both as per Martin himself.