In the article, it mentions the Scarlet Speedster disappearing into a crisis, which comic fans readily assume refers to the Crisis on Infinite Earths, the gigantic comic arc that had the Anti-Monitor as its main villain.
I’d expect a lot of offscreen fighting for that.
We can possibly expect a very pared-down version of that, with Monitor bringing the Earth-1 heroes together with Supergirl and Batwoman (from whatever Earth she resides on) to take on another entity of equally immense power.
While we’re obviously not sure yet how The Monitor will make his way into the lives of Oliver Queen, Barry Allen and Kara Danvers, his existence and his comic story are a huge arrow pointing back to the 2024 newspaper headline that has driven parts of The Flash’s story since Season 1.