Does Warwick's 'When I Attack' ability interact with Cannon Barrage during combat?

Ruling: Yes, Cannon Barrage can be played in response to Warwick's ability on the Initial Chain. Cannon Barrage will resolve first, dealing damage to units, and then Warwick will see the damaged units and kill them.

Sequence:

• When I Attack and When I Defend abilities trigger and go on the Initial Chain during Showdown
• Cannon Barrage (as a Reaction) can be played in response to abilities on the Initial Chain
• Cannon Barrage resolves first, damaging units
• Warwick's ability resolves, killing all damaged units

Nuances:

• When I Move abilities trigger before Showdown, not during the Initial Chain
• The Initial Chain is part of Combat and Showdown