You can try two things here, change the cylinder or make a new key, either way the cylinder has to be taken out, once the cylinder is out look for a ID number on the cylinder, that's the sequence number to make the key, take it to a locksmith also take the cylinder

Lol maybe someone put blue tac in it

Do you have another key you can try? Maybe the one in hand is damaged or worn enough it's not hitting the ignition lock?

The steering wheel lock isn't on is it? Pull your steering wheel over a bit and while holding it over turn your key

So I have a 2003 Nissan Altima and my key will not turn in the ignition. I have done the whole steering wheel thing and nothing. I tried spraying wd-40 and nothing. The car also is in park. My neighbors tried and and after a while they got it by moving the key up and down and they turned t off again and they tried it again and still locked. Can someone help me please. It's really stressing me out! :(