Hitman 3 is about to be launched on January 20 for the Xbox Series X|S, Xbox One, PlayStation 5, PlayStation 4, Google Stadia, and PC exclusively through the Epic Games Store (affiliate link). That PC release is a timed exclusive, so if you want to purchase it elsewhere you may need to wait for about a year from now. On the Nintendo Switch, the release will happen on the 20th as well only it will be playable via cloud streaming technology. This means you will need a permanent Internet connection in order to play.
In Hitman 3, you play as Agent 47 and return as a ruthless professional hitman, hence the title. You will embark on "the most important contracts of his entire career."