It's common for people to export video or PNG sequences from Spine to After Effects for further processing like camera movement or VFX.
It's also common to export a PNG sequence that is frame-by-frame animation from After Effects and bring it into Spine, for example as a mesh sequence. Spine can manipulate and bend the images, adding to the effect of the frame-by-frame animation.
You won't be able to access all the Spine functionality in After Effects, and vice versa, but you can do a lot between the two programs by transferring frame-by-frame animations.
