I was in Peru recently and flew back to the US on a single United ticket CUZ-LIM-EWR-xxx. I don't see any recent threads on this and wanted to share my experience (warn others) ...

- There is no baggage interline. Although the LA/UA systems "talk" (United app could see my LA bag tag nbr), there is no transfer. There isn't even a transfer desk. You must collect your bag in LIM, walk out of the airport, re-enter (it's only 100-200 feet), and start everything over again with United check-in.
- LIM has separate lines for domestic vs international security, although I'm not sure why. The security standards for both seemed equal.
- US-bound flights have additional gate security, which is about a dozen airport employees searching every single carry-on. Fortunately, with so many staff, it didn't really delay boarding much.

I naively booked a 2h connection assuming this would all run smoothly, but I knew I had the IAH flight 2h later as a backup if needed. The whole process above took about 1:15, so I arrived just in time for boarding. 40 minutes of this was waiting for LA to offload my bag from CUZ....

I had a great trip, but LIM is a mess. I hope this helps others planning a similar itinerary.