sorry if this question may sound a bit stupid, but bear with me.

so, currently i am proficient in python, c++, HTML, and am planing on learning Java and qt soon. however whenever i look for a job online for, say, c++, they always require me to know 2 or 3 other languages, such as c#, Java, and .NET. my question is, why do employers need you to know so many different languages if the job posting is for c++? I know the languages are sometimes required to be integrated with one another, but where can i learn how to do that? is there a framework which does this?

I know this question may sound very noobish but i'm a bit confused right now, and any help will be greatly appreciated.

Though the job might have been posed for C++, sometimes employers like people who have multiple skill sets. So in one recruit the employer gets an employee who can work in C++,C#,Java etc. Also these languages are pretty similar to C++, so learning is easy for someone who has already learnt C++