When it comes to describing someone or something being "in tune", there are several synonyms to choose from. The term "harmonious" can be used to convey the sense of two things being in sync or in agreement with each other. "Aligned" is also a great way to describe things that are in tune, particularly when it comes to ideas or goals. Other synonyms for being in tune could include "coordinated", "corresponding", "at one", "in step", and "matching". Overall, there are numerous ways to describe things that are in tune with one another, each offering slightly different interpretations of the concept.