There was no Katie is this week’s episode of Arrow and I don’t think she will be in the next one as it’s more on Oliver and John but we do no that Katie will be back in episode 19 called The Dragon
DIAZ SETS HIS SIGHTS ON THE QUADRANT — Looking to expand his empire, Diaz (guest star Kirk Acevedo) and Laurel (Katie Cassidy) meet with The Quadrant, a coalition of mafia families who run national organized crime. Meanwhile, after Oliver’s (Stephen Amell) recent decision, Felicity (Emily Bett Rickards) and Curtis (Echo Kellum) double their efforts on building Helix Dynamics.