Many of William Shakespeare's plays are still taught and performed today because they are found to still be relevant in today's world. The themes of his plays are those which still engage readers ad viewers alike. These themes are the types which are timeless, meaning they can appeal to the people of today and the future.
As for the themes which make Macbeth universal in nature, ambition, guilt and evil all are apart of today's society. Without ambition, some people will never be able to achieve the things in their life they deem necessary. Many people have something in their life which makes them feel guilty (granted, most have not committed murder, but the guilt still exists). Lastly, as long as good exists, evil will be there to counteract it.
Essentially, Macbeth is universal in nature because the themes brought out in the play are those which people can relate to.