Lighting is used to illuminate 3d objects not a cubemap (which can be a light source by its own), so if you have no 3d objects in your scene, you don’t need any lighting.
Also why are you using real spheres for you cubemap, you can simple change the skybox material on the fly.
But @misher the image is on a 3D sphere (did you see the image?) and the the shader is mapcube so I feel like I’m in a real world environment.
I need to illuminate a picture that is hanged on the wall of the room I have the 360 degree image of.
I need to be able to insert a spot light for this element in my photo,
and I’d like to do it in unity.
otherwise I can:
change 360 image in photoshop
perhaps create a sphere with this texture as a model in Blender and than import as a 3D object