With VTK 9, there are two ways to get the libraries and include directories that you need.
The first way is to list the modules that you need in the find_package statement. Then you can use ${VTK_LIBRARIES} for linking:
find_package(VTK COMPONENTS CommonCore FiltersCore IOImage)
...
target_link_libraries(NewMarchingCubes PRIVATE ${VTK_LIBRARIES})
The second way is to list the individual libraries with target_link_libraries():
find_package(VTK REQUIRED)
...
target_link_libraries(NewMarchingCubes PRIVATE VTK::CommonCore VTK::FiltersCore VTK::IOImage)
The include directories are automatically set when you use target_link_libraries().