If a unit with an attack/defend trigger is removed from the battlefield in response to the trigger, does the trigger still take effect?

Ruling: The trigger will always still resolve, but it rechecks legality. If the unit has "here" in its text (like Yasuo), the effect won't work if the unit is no longer on the battlefield when the trigger resolves.

Sequence:

• The attack/defend trigger goes on the stack
• If the unit is removed (e.g., by Fight or Flight) in response
• The trigger still resolves
• The game rechecks legality based on the trigger's text
• If the trigger requires the unit to be "here" and it's not, the effect whiffs

Nuances:

• Most attack/defend triggers have "here" in their text, which means they require the unit to still be on the battlefield
• Yasuo specifically has "here" on his text, so if he's moved to base/trash, his damage effect won't inflict any damage