Developer IO Interactive speaks in a Noclip documentary about a continuation of Hitman 2 and more plans. The current series around Agent 47 is definitely planned as a trilogy: IO boss Hakan Abrak explicitly talks about Hitman 3. According to Noclip host Danny O'Dwyer, the developers also think about publishing Hitman 3 again in episodic format after Hitman 2 as a complete package appeared.
"Hitman is planned as a trilogy. The future looks bright – we want to realize the so-called World of Assassination in its entirety. Once completed, this World of Assassination will be a big game starting with Paris in Hitman (2016) and ending with the final location of Hitman 3. "
However, it should be some time before the finale appears Because the main studio of IO Interactive in Copenhagen is currently working on a new, secret project, which is dealing with a completely new brand. The current development of Hitman 2, as well as the concept of Hitman 3 was outsourced to the January 2019 founded branch in Malmö. They are currently working on free and paid DLC extensions to the current Hitman 2.