PSA: If you need a Lisp that talks to C++, Common Lisp has had seamless C++ interop in the few years thanks to the CLASP implementation. It should be fairly mature by now, I understand it was born to be used in serious projects.
In jank, you just require the C++ headers, like you would in C++, and then you access whatever you want from them, like you would in C++. jank's type system is the C++ type system. jank also compiles to C++. jank includes a Clang-based JIT C++ compiler to make all of this possible.