George R.R. Martin is still writing The Winds of Winter — as far as we know. The author has claimed the sixth installment of his A Song of Ice and Fire series be completed next year. However, with a story this complex and popular, the editing process is likely to be a lengthy one. A completed draft is far from the end of the road.
In the meantime, fans can find some joy in the clues about Martin’s plans for The Winds of Winter in James Hibberd’s behind-the-scenes dive into the HBO show's eight-season run, Fire Cannot Kill a Dragon. Martin has already revealed that Hodor’s death will be different in the sixth book and expressed dismay at Lady Stoneheart’s exclusion from the HBO series.
One notable story arc that Martin pointed out was Petyr "Littlefinger" Baelish’s treatment of Sansa Stark. On the show, Petyr betrayed Sansa and arranged for her marriage to Ramsay Bolton, the wicked bastard son of Roose Bolton. This alliance ultimately led to Sansa’s rape, imprisonment, and overall abusive treatment by Ramsay. When Sansa asked Littlefinger if he had known about Ramsay, he claimed that he didn’t. It was an odd response considering his vast network to obtain intelligence.
In Hibberd’s book, Martin confirms Littelfinger’s actions will play out differently in The Winds of Winter (via Insider):
“My Littlefinger would have never turned Sansa over to Ramsay. Never. He's obsessed with her. Half the time he thinks she's the daughter he never had — that he wishes he had, if he'd married Catelyn. And half the time he thinks she is Catelyn, and he wants her for himself. He's not going to give her to somebody who would do bad things to her. That's going to be very different in the books.”
In the books, Petyr had already arranged for Ramsay to marry Jeyne Poole, Sansa’s childhood friend who was trained to take Arya Stark’s place. However, Littlefinger’s actions in Game of Thrones set off a chain of events that ultimately led to the Battle of the Bastards — an event that reestablished House Stark as the ruling family in the North and allowed them to reclaim Winterfell from House Bolton. The battle hasn’t happened in the books yet, but Petyr’s story being “very different” in The Winds of Winter could alter the bloody conflict in a major way.
The Winds of Winter’s lead-up to the Battle of the Bastards has already diverged from the show, but there are still chess pieces in place that could change the final outcome. What the show termed the Battle of the Bastards may be nothing more than Stannis’ Battle of Winterfell in the books.
Currently, Petyr has promised Sansa rule of Winterfell (currently under Roose’s control) by way of her marriage to Harrold Hardyng, Lord Robert Arryn’s cousin and heir to the Vale. Meanwhile, Stannis Baratheon, the rightful heir to the Iron Throne, decided to overthrow House Bolton and take back Winterfell in a bid to bring the North to his side against the Lannisters. With Stannis only three days away from reaching Winterfell, Roose sets his army loose in an attempt to take Stannis down beforehand.
Stannis dies before he ever gets to Winterfell in Game of Thrones, slowed down by a blizzard and Ramsay’s army. He burns his daughter Shireen as part of a spell, which causes his army to abandon him altogether. Wounded, Stannis is killed by Brienne of Tarth as revenge for his murder of Renly. What’s more, Roose is killed by Ramsay to thwart his father from naming his newborn son as heir.
With Stannis and Roose both still in place in the books (and Theon warning Stannis of Roose’s army), the Battle of the Bastards could end with an entirely new winner. Winterfell could still be liberated, but it may be Stannis who leads the charge instead of Sansa and Jon (who's still dead in the books and may not come back as easily as he did in Game of Thrones). Of course, if Jon is resurrected, he could still be a player in the coming battle.
Sansa remains integral to the conflict. In the show, she calls upon Littlefinger's assistance against Ramsay without revealing her plans to anyone else. This could still happen in the books. It’s possible that Stannis’ potential victory could help Sansa regain power over the North, especially since she wants to restore Winterfell. Who knows? She might even decide to back his claims for the Iron Throne. These moves could change everything moving forward in the books. Plus, if Roose and Ramsay die or are defeated, then there would be no need for another battle.
Ultimately, Petyr's decision not to marry Sansa off to Ramsay in the books will change a lot of other plot points moving forward. It may seem like a small alteration, but we’ve seen how one wrong (or right) move changes everything. And Littlefinger knows better than anyone how to play the game of thrones.