Thanks all for the feedback on this flight.
I have another international connecting flight out of Inchon (1 hr 20min layover at Inchon). I will likely miss this connection even if I catch the next DL out of SEA. It will be a layover of over 18 hours or 24 hours in Korea then depending on which flight I take the next day.
I think will have to pick up luggage and go through immigration . Correct?

I did check flight tracker for ORD-SEA for this flight and track record is bad if a delay for more than 30 minutes at o’hare.