create a nuget package with dll in c# and c++

Question

In my C# project I use purely C# dll, but for some functions it is possible to use only C++ libraries and dlls. What I am trying to do is create a Nuget package consisting of C# dll and C++ dll. Using Nuget Package Explorer and following the procedure for creating a Nuget package, I placed the C# dll in the "lib" folder and the C++ library in the "content" folder. Created the Nuget package, I tried to import it into my project, but after building, in the output path there is only my dll in C#. What should I do to be able to import the dll in cpp into the output of my project?