I filed for unemployment in May 2020 but did not receive any payment until April of 2021. Do I need to claim these benefits for 2020 or 2021?

If you did not get a 1099-G for 2020, nor any unemployment benefits paid to you, then you do not have to claim these benefits for 2020. 

I had the same thing happen. I filed in October of 202 but the case was under appeal. I received the unemployment in May of 2021. I did not receive a 1099 from the state of Michigan. Do I need to file an amended return or claim it on my 2021 taxes?