This has been speculated since the WWE NXT - USA Network TV deal was announced, but there is said to be a real possibility that we will see a sixth NXT Takeover special in 2020, according to a new report from @Wrestlevotes.
WWE increasing the number of annual Takeover events to six would depend on the success of the show and how the numbers look on the USA Network.
There's no word yet on when the sixth Takeover event would be held, but the current schedule obviously makes finding a spot for that extra show difficult. The 2019 Takeover schedule had events taking place during Royal Rumble weekend in January, WrestleMania 35 weekend in April, first weekend of June, SummerSlam weekend in August, Survivor Series weekend in November.
As noted earlier this week, MKM Partners analyst Eric Handler mentioned in a note to investors that WWE now has additional opportunities to further monetize the NXT brand, including the possibility of raising the number of annual Takeover events from five to as many as twelve. It's highly unlikely that WWE would ever do monthly Takeover events, but anything is possible. Handler wrote in his note, "We anticipate WWE management could look to further monetize the NXT brand with international TV deals either through pay-TV or free to air networks."
WWE has held five Takeover events per year since 2015, except for 2016, when they did four. There were just four Takeover events in 2014, following the first-ever Takeover event in late May of that year.