In Dying Light 2 we will see different steps of zombie evolution.
Dying Light 2 is set 15 years after the first game.
During the Broadcast mission, when you come across the dying soldier, his name is Leon and he mentions another soldier named Chris. This is a homage to Resident Evil's Leon Kennedy and Chris Redfield, this can be confirmed by looking at their dogtags.
Whilst looking at the scenery at the start of the game, Spike says "I wish Crane could be here to see this". This suggests that Kyle Crane, the playable character from the original game, passed away in between the events of the two games.
Dying Light 2 will be create on C-Engine. It was like a Chrome Engine 7 , but Techland Made a Rebranding. It will be more powerful, and with new functions, and also new technologies.