Similarity to IT never occurred to me, but watching the trailer I think I see what you mean.. a team of kids, cycling time periods... they're not united and bonded like in IT though, at least not at this point. And the adults play an equal or larger role. The Killing has caught my eye, but I haven't watched it. I'll check it out if you think it's good.
I haven't seen Dark yet, but I was thinking, based on the trailer alone, the similarity was more in the complacency and illness of the town which allows evil(however defined) to endure and the recurrence of the evil involving the death of the youth.
Did you watch the full series?