How do you get into 1998 528i bmw trunk with out key?

To open a 1998 BMW 528i trunk without a key, you can try using the manual release mechanism located inside the car. If that's not accessible, check if the back seat can be folded down to reach the trunk from the cabin. Alternatively, you might need to use a slim jim or a similar tool to unlock the trunk latch, but this approach could damage the locking mechanism. If all else fails, consider contacting a locksmith or a BMW dealership for professional assistance.