Interesting article in the The Atlantic about subdermal microchips, discussing a few health-focussed implants and related research.
I got myself chipped a few years back because my phone didn’t have a fingerprint reader but NFC capabilities. I used the chip in my hand to unlock the phone all the time for a year or so.
These days, my RFID tag carries some emergency data but nothing else (name, birthdate, blood type, city of residence). I wish it could do more, tho.