If you didn't purchase the game through official channels, the safest move is to delete the file and run a full system scan with Malwarebytes or Windows Defender.
The official game by Crowbar Collective is simply titled Black Mesa . While the developers released a "Definitive Edition" update in 2020, it was a free patch delivered directly through Steam . It is not distributed as a standalone compressed archive like a .rar file. Black-Mesa-Definitive-Edition.rar
Legitimate modern games are rarely distributed via random .rar files on third-party hosting sites. If you didn't download this from a verified storefront like Steam or GOG , it is likely a "repack" at best or a virus at worst. If you didn't purchase the game through official