2016's Hitman was a return to form for the series. Returning from the divisive Absolution are living and breathing worlds that present you with a puzzle and all the freedom in the world to solve it. This series is known for giving you a target and setting you loose to silently - or not so silently - take that target down, and this game more than delivers on that front.
The massive maps, extensive ways to go about assassinating a target and massive collection of toys to do it with make this one of the most replayable games in recent memory. You can sink hours upon hours simply on one map, as you find target routes and weaknesses in security.
Hitman is a game with an absolutely remarkable amount of content, and if you've somehow managed to overlook it, it should be the next game on your radar without question.