Nothing! Well, you should bring your phone, car keys, and mask, but beyond that, try not to bring anything else. When they bring you inside, they ask you to empty your pockets so they can scan you with a metal detector. 

They have strict rules on what you can’t bring inside, including strollers, backpacks, large bags, outside food or drinks, weapons, and cameras (any DSLRs and even go pros). That last one is the big one people miss, and we saw multiple people run back to their car to put their cameras away. Coat check is meant only for coats and nothing valuable.