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

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 build, 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?