MARVEL Tōkon: Fighting Souls | CIS

Check that your Steam account country is one of: Armenia, Azerbaijan, Georgia, Kazakhstan, Kyrgyzstan, Moldova, Ukraine, Uzbekistan. The region is shown under "About Account" next to "Country"; the key will not activate on an account with a different country.

In the Steam client: launch the app and sign in to your account.

In the client's top menu, click "Games" and select "Activate a Product on Steam…".

Enter the key from the email and follow the wizard's prompts — once confirmed, the game will appear in your library and be ready to download.

Via browser: open store.steampowered.com/account/registerkey and sign in to your Steam account.

Paste the key into the "Product Code" field, accept the Steam agreement and click "Continue" — after successful activation, the game will be added to your library.