Koei Tecmo has announced that Hyrule Warriors: Age of Calamity has shipped over four million copies. This information is based on worldwide sales data available.
The game received a strong review from us, both for the base game and the DLC. If you have not seen the reviews, they are here and here
Back in April, the game was at 3.7 million copies sold, and it is also the highest-selling Warriors/Musou game so far.