Apple recently released a new tracking device called AirTag. It is similar to the small Tile devices that have been in circulation for many years in that they help you find misplaced items like your keys or a bag. They locate your stuff and work like this. I pre-ordered a 4-pack of them last month but they aren't scheduled to arrive until June. Maybe it's because I got custom engravings on the back of them.
Perhaps the most obvious use case for these new AirTags is to place one inside of your checked bag(s) when you travel. There's nothing worse than an airline losing your luggage and you not knowing where it is. So I can see myself using one of these every time I travel. Hopefully that will be very soon.
But the other really interesting thing about these devices is that they run on Apple's "Find My" network, which is the same network that allows you to find your other iOS devices if you happen to misplace them. This is essentially a decentralized mesh network that is powered by all of Apple's devices around the world, as opposed to some big telco network.