CD Projekt's summary of its 2016 financial results reveals, in case there was any question, that The Witcher 3: Wild Hunt, and the entire Witcher trilogy, have been a huge success. Total sales of The Witcher 3 over the year-and-a-half following its release exceeded $250 million, and the trilogy as a whole has now sold more than 25 million copies.
That sales figure isn't broken down by title, but according to Wikipedia the first game had moved about two million copies across its original and Enhanced Editions by 2010—that's PC only, by the way, making it an even more impressive accomplishment—and CD Projekt announced in late 2013 that it and The Witcher 2: Assassins of Kings had collectively sold six million units. The Witcher 3 sold that much all by itself in just six weeks following its May 2015 release, and in March 2016 the studio said the series had surpassed 20 million combined unit sales—and that was before the release of the trilogy-ending Witcher 3: Blood and Wine DLC.
In fact, the summary states that even though CD Projekt sunk "unprecedented" amounts of money into its ongoing projects in 2016—Cyberpunk 2077, Gwent, and the Witcher 3 expansion Blood and Wine—it was still able to put up a "positive cash flow" of $52 million for the year.
"For years we have consistently prioritized quality and focused on a limited range of products. The persistently strong sales of the entire The Witcher series vindicate our approach and contribute to long-term appeal of our releases," CD Projekt president Adam Kiciński said. "This year we will continue to expand The Witcher brand—it is, after all, the year of Gwent. We’re in the process of organizing the game’s first major tournament, with a $100,000 prize pool. Another crucial round of beta tests will commence in spring, with the retail release to follow in the second half of 2017."
I did not have the nerve to reach out to original Witcher author Andrzej Sapkowski for comment, but I do honestly feel badly for him.