[oriolid]

As far as I know, Unity uses C# as scripting language and does the heavy lifting in C++. And the usual way for making mobile builds for Unity games is converting everything to C++ with IL2CPP and then compiling that to native binary.

[Kwpolska]

As far as I know, web browsers use JavaScript as a scripting language and do the heavy lifting in C++.

Your average Unity game developer does not do anything in C++. The engine itself is implemented in C++, but the game logic written by game developers is in C#.