Was revealed during the first official PlayStation 5 event
Hitman 3 Is The Final Installment In The World Of Assassination Trilogy.
If you throw specific items at specific walls in the Berlin level, a secret exit will be unlocked next to a bike. 47 will ride it and escape the level flying while featuring the moon in the background. This is a reference to Steven Spielberg's 1982 classic "E.T. the Extra-Terrestrial".
In the first mission of the game, "On Top of the World", if the player drowns someone in one of the many electric toilets scattered around the level, the toilet will attempt to analyze what has been put into its bowl, with one of its remarks humorously stating "I am in doubt if you are actually human."
On the Ambrose Island map, there is a gravestone marked Threepwood, being a reference to Monkey Island protagonist Guybrush Threepwood.