Is there a way to connect a LAN device to another device over the internet?

I'm not the most well versed in networking stuff, so this might be a stupid question.

In theory, couldn't you just connect the device to the network, forward the port, and have the other network do the same thing?

it would go something like: deviceA <-> networkA <-> networkB <-> deviceB

Security issues aside, couldn't this work? It probably wouldn't, I feel like it's too simple.