According to the Wrestling Observer Newsletter, the current plan is to do five NXT Takeover events in 2018. The fifth event is set to take place on Saturday, June 16th in Chicago during WWE’s Money in the Bank PPV weekend. It has been reported for several times that MITB will now be positioned as one of the “big five” events instead of the “big four” events that WWE has been doing which is Royal Rumble, WrestleMania, SummerSlam and Survivor Series. There were also five Takeover events during 2017 as Takeover: Chicago took place during Backlash weekend.
Source: Wrestling Observer Newsletter