I have a 1998 XK8 ignition key

I

have a 1998 XK8 and the ignition key doesn’t work to start the vehicle, but the valet key works any ideas

Wrong forum, this is the one for the original XK120/140/150.

I have moved it to (I think) the correct forum.

Configure the key(s) to the car with appropriate computer and software.
There will likely be a DTC P1260 in the ECM indicating KEY NOT RECOGNIZED.