That's a whole other topic. RFID chips have a much more limited range than GPS devices, so the RFID scanner would need to be in range (depending on the capability of the particular devices). Currently, the most powerful RFID tracker only has a range of 500 yards.
RFID trackers are useful for things such as tracking kids in a school environment, or finding a lost dog in the woods, but not for long range monitoring. Not yet, anyway.
What RFID chips *can* do is store data. They can track your purchases and store information about your day-to-day habits or medical records.