Did you know most people don't know that Obamacare is the same thing as the ACA? Check out this video Jimmy Kimmel made:
One of Trump's biggest campaign promises was to "Repeal and Replace Obamacare". And he did just that with the American Healthcare Act. This one is different because it does not make it mandatory for states to provide for essential benefits, those with preexisting conditions will have higher premiums (outlawed in the ACA), and give tax breaks to the wealthy. There has been severe backlash towards this act because it is seen to help the rich and hurt the poor and leave millions uninsured.