Harmony is diversity. In music it is different notes that sound good together. In life, it means that completely different people can cooperate together very well. The outcome coming from a combination of different personalities and skills is much more interesting.
People have different thinking, approaches to problems and ways of working things out. But there's a strength in differences. If a team learns how to embrace everyone's strength, each teammate can give its best and the team itself will be unstoppable.
That's the power of diversity. If everyone would sing the same note, the result would be monotony.