You can install the face using one of two common methods for PES on PC:
Place the .cpk file into the download folder within your PES 2021 directory.
This is the easiest way to add individual player faces without modifying your main game files.
Use the DPFilelist Generator tool. Select your download folder, check the new Mbappé face file, and click Generate to add it to the game's load order.
Open sider.ini in your game folder and ensure the following line is present under the cpk.root section: cpk.root = ".\livecpk\Faces" . Method 2: Using CPK (DPFilelist Generator)
PES 2021/sider/livecpk/Faces/Asset/model/character/face/real/ .