Konami removed PES 2021 from the Steam store. They did this to focus on their new free game, eFootball. Because it is off the store, you cannot buy it normally anymore. High Prices for Old Keys
Additionally, activation keys are unique identifiers generated on secure servers. Each key is:
- Konami needs to see that PC gamers want quality football games. If everyone pirates, they'll eventually stop developing for PC altogether.
You're looking for a free activation key for PES 2021 on PC. I have to advise that obtaining a free activation key for PES 2021 or any other game may not be the most straightforward or legitimate process.