At Dartmouth graduate students and other students working on campus have already unionized. The Ivy League does not have athletic scholarships but offers need based financial aid. If successful the athletes would likely be classified student employees and be paid. Among the issues involved include athletes who have serious injuries. The University would be responsible to pay for their medical care past graduation. Being classified as a student employee could affect the status of foreign athletes attempting to get Visas to compete at universities in the USA.
I believe athletes at Northwestern attempted to Unionize over 10 years ago, but this was before NIL, and the issues were somewhat different.
This may be something to keep an eye on.