Does taking community college classes in highschool improve my chances to get accepted into an Ivy Leauge school?
No
Well, it is one way to show rigor, but not the only way. College classes can have very different curricula and syllabi. With AP and IB on your transcript, a college pretty much knows exactly what you’ve studied. They’re more or less standardized.
CC/DE classes are more useful if you plan to attend a public college, especially one in your home state, than to an ivy league aspirant. Unless, of course, that ivy hopeful has exhausted all the options offered by his/her high school. Some states will guarantee those credits will transfer to that state’s public four-year schools, but there are no such guarantees they will transfer to ivies, or any private college.