Try clearing the code if you can (with a reader or at an Autozone or a friendly mechanic). See how soon it comes back. It wouldn't cause any immediate harm unless the engine has other symptoms (like much worse fuel economy than before, rough running, etc) but you should replace it sooner or later for the best fuel economy, performance, and longevity, or if you have an emission test coming up.

Usually replacement is simple if you have the exact matching sensor as the original.

In my case I cleared the code and it came back after a month or 2. Cleared it again and it came back sooner. Then I replaced the sensor. The code I had was for "slow response".