A question like this really gives you the opportunity to be creative and bring in your own personality. There are thousands of modern songs we could probably relate to this play, but it's up to you to choose the ones you like. A good place to start would be to remind yourself where we are in the play in act 4.

In act 4, Macbeth has already begun to break down mentally. He has just seen the ghost of Banquo, whose death he engineered, and at the beginning of act 4, he goes back to the witches to demand further information. At this point, he receives false reassurance in the form of the prophecy that "no man of woman born" can hurt him, but the witches also tell Macbeth that Banquo's sons will indeed be kings.

Macbeth learns after this that Macduff has left Scotland for England, whereupon Macbeth, furious, sends his men to murder Macduff's wife and children. Macduff and Malcolm, meanwhile, resolve to save Scotland from Macbeth, who they now know is "treacherous." Macduff learns that his wife and children have been killed. Malcolm encourages him to let his grief turn into powerful anger.

So, it occurs to me that a song from Macduff's perspective would be interesting here. Macduff and Macbeth were formerly friends, or at least colleagues; now they have some very bad blood between them. The immortal words of Taylor Swift in "Bad Blood" resonate somewhat, particularly the comment "if you live like that, you live with ghosts." Macbeth isn't sorry for what he's done, and he's certainly living with ghosts! Meanwhile, the "bullet holes" he has metaphorically generated (the deaths he's caused) can't be fixed with "band aids." Macduff is going to have to take drastic action to deal with this bad blood.

Alternatively, we could think about things from Macbeth's perspective. How is Macbeth feeling here? He's starting to spiral. Things have gotten out of hand for him, but he's committed. Bastille's "Pompeii" sounds to me like something Macbeth might be thinking: "we were caught up and lost in all of our vices." Meanwhile, "the walls kept tumbling down / In the city that we love." Macbeth and Lady Macbeth probably wish they could go back to the way things were before, but things have been set in motion now, and it's too late for them.

I hope these give you some idea of where to start!

An appropriate song for Act 4 is "Quiver" by Theory of a Deadman. Macbeth is responsible for the murder of Macduff's family in this act, so this song could be an anthem for Macduff.  Macduff would believe by this point in the play that Macbeth would "leave [him] at the side of the road to die." And, undoubtably, Macduff does "quiver at the thought" of Macbeth and his pending revenge. he takes his anger over his family's brutal murder and uses it for motivation. This song's lyrics are perfect for Macduff in Act 4: What doesn't kill you makes you stronger.

My other choice would be The Kinks' "Mr. Big Man" in relation to Macbeth himself.  The first-person narrator of this song laments, "I bet that you're losing count / Of the people that you used."  Sounds a lot like our protagonist!  This song continues to accurately describe Macbeth in a later verse:  

You schemed and connived. 
You pushed and you lied, 
Till you at last became a star. 

I hope these help!