Just replaced the key ignition switch and the car will turn over but will not start.
The chip in your new key hasn’t been programmed to your car.
You’ll need a mobile locksmith that has the capability to program it to your car to come to you, or have your car towed to a locksmith or the dealer.
If you still have your old key, you might try holding the head of it next the new key while trying to start.
You could also take the new cylinder to a locksmith and have it re-keyed to your old key.