There's no definite word on when the next 'Game of Thrones' novel will come out. Martin has been occupied with various other projects and the complexity of the story he's crafting for this one. He's known for his detailed world - building and character development, which takes a great deal of time.
There's no official release date yet. The author, George R.R. Martin, is still working on it. He's known for taking his time to perfect his work, so it could be a while before we get to read the final installment.
The publication date of the 'Game of Thrones' last novel is uncertain. George R.R. Martin is a meticulous writer who likes to perfect every detail. He also has other projects and commitments that might be affecting the progress. Additionally, the story is so vast and complex that it takes time to tie up all the loose ends. Fans have been waiting for a long time, but it seems they'll have to be patient a while longer.