Cannot turn key off

You have an issue with the shifter. There is a solenoid on the shifter that tells the ECM what gear the shifter is in. If the shifter is not in park it will not allow you to release the key. Think of it when you try to turn the vehicle off in drive and remove the key. You are not able to because the vehicle needs to be in park so it doesn't roll away.

Let me know if you have questions and we can go from there. Thanks