Couple things that would need to happen:
We hold on to Brogdon for the whole season
Things don't work out for the Lakers and they need a PG who can facilitate and space
Lakers don't make a deal for a PG at the deadline (before Vando can be moved)
Lakers
They could use a PG who can facilitate either alongside LeBron or when he's off the floor. Brogdon can also play off ball and doesn't need the ball in his hands as much as DLo to create offense. He's also a better defender than DLo. Vando would be a bit of a loss for the Lakers, although Rui's played well for them at the 4.
Blazers
Vando is exactly the kind of young, defensive-minded, 3&D capable 4 the Blazers need for the future.