Over years and after the end of WWIII many world religions faded into obscurity.
While there are still people who practice old world religions they are mostly radicalized versions of the religion they once were before the war. 

In Megacity cults are much more prevalent than organized religion, and mostly founded for personal and financial gain. Exorbitant tithes and donations being required are very common. 

One major cult (referred to as Gate) is secretly run by the CEO of Macroplush. The cult's purpose is to turn its followers into violent anti-work extremists, and preaches messages of "taking power back from the man" and "creating your own destiny", often encouraging acts of violence and terror to be committed on the bosses of the working man. 

However the leader's real goal is to recruit employees of his own competition, therefor being able to indirectly murder the CEO of any company that opposes him.