There could be food or other particulates underneath the key or on the keycap itself that may be making the key either stick or not move.

There could also be soda residue on the keyboard itself making the keys stick to it, make sure that it is wiped away.

Inspect the keyboard and the caps one last time to make sure there isn't anything left that could make the keys stick.

If there is nothing underneath but the keys are still sticking, replace the keycap with a new one.