It was coming and has been confirmed: TheCW cancelled Batwoman and Legends of Tomorrow.
On one hand it's surprising, as the network still keeps on the air shows that have been on much lower ratings for years (Dynasty, In The Dark, you name them); on the other hand, it was coming, as TheCW was being sold and it was just a matter of coming to an agreement on which shows were going to continue and which ones were getting the axe.
So now the Arrowverse is down to just The Flash and Superman & Lois