Is Wicca related to any other religion?

Yes and no. Yes because Paganism (the root of Wicca) is actually the oldest religion in the world and The Pope (head of the oldest Christian faith) admitted in the 1300's to stealing not only Pagan worship sites, dates and etc. but a lot of rituals and etc. from Pagans (in an attempt to get Pagans to convert to Christianity). So Paganism and in a way Wicca is actually the root of all religions.

However, Wicca is actually a very modern religion on its own. Gerald Garner updated and transformed The Pagan Belief System to incorporate other traditions and allow a more open belief system in the 1940's. This is what we know as Wicca.