Theory of Mind is a concept in developmental psychology, in which a baby or toddler realizes that objects can have a point of view, intentions, and plans. It is generally discussed as a "theory of other minds", as the toddler makes the inference from their own mind operation to conclude that active objects in its world also have minds.
Theory of Mind is therefore not an ANSWER to the mind-body problem, but a fundamental precondition to recognizing that there IS a mind-body problem.
In the context of AI, AI researchers have discovered that simple algorithmic and neural net processes, while useful for some tasks, end up failing when applied to complex intentional behavior, such as dealing with humans. This is, presumably, why humans evolutionarily developed a theory of mind ourselves -- to work better than algorithms alone. However, theory of mind programming, in which one creates a toy model of the inputs and intentions of objects or communication parties, and then uses this toy model to interpret and predict actions -- is immensely complex. And apparently, per the abstract of this paper, the test databases to see if a programmer gets better results with a theory of mind or not -- are not challenging enough, so theory of mind isn't needed to deal with them, even if it is needed in the real world. I don't think this paper has much of philosophical interest.
What IS of some philosophical interest, is that several of the philosophy of mind schools basically advocate to ignore theory of mind. This would include behaviorism, eliminative reductionism, and functionalism. And if AI researchers find that THEY need to account for "theory of mind" to actually do AI well, then these meta-theories that deny that mind plays a significant role in the universe -- are pretty decisively refuted.
