The average lifespan of a panda is around 20 years.
Pandas live on average around 15 to 20 years which is a bit longer than some dogs live.
There was a panda that lived to be 38 years old before it died and that 38 year old panda was kept in captivity and well cared for.
So it's possible if the panda is not living in the wild that it may live more than 20 years.
However even in the wild a panda may live longer than 20 years.
Just like humans can outlive their normal lifespan the animals including the panda bear and any other bears may live longer.