The key isnt starting the car

Absolutely. Could also be that the smart key has a dead battery or has been compromised by moisture, etc.

Can you still lock & unlock the car with the smart key? If so, the battery is not dead, and you should look next at the ignition itself. Is there any response when you put the key in? Can you turn it? Are there signs that your battery is drained (dim/no lights work, etc)? If you are getting no response when you put the key in and you can turn it, and it still works to unlock your car and you can verify that you have battery power, start by checking your fuses. The ignition and starter fuses would be the first to check.