During the Geralt and Ciri reunion Ciri tells Geralt where she had been hidden for some time. She recalls people with metal in their heads fighting over distance with megascope-like devices and flying ships.

Sounds sci-fi to me.

You think CD Projekt want to combine these two franchises or is this something from the Witcher lore?

This is probably what you would call a easter egg.

Kind of like you find some hints off Mass Effect in Dragon age.

With the way Ciri's powers work it's more than likely not in the same "universe". They could make her jump to the Zelda universe and fight Ganon if they wanted.

It's just a small easter egg (if it is at all). I don't think there's any chamce for legitimate crossover potential.

It's a common misconception that Cyberpunk is CD Projekt's property, when in fact it's a series of table top RPG games that have dated back to 1988.

We have a winner.

I took it as a reference to WWII in our real world dimension. Ciri is also responsible for the Bubonic plague within the TW universe which is known to them as the Catriona plague. She travelled to our dimension and brought back fleas in her clothes which infected the rats within the TW universe.

SInce they are both based on completely different licenced IP's I doubt it.