Are you possibly thinking of one of these shows?
* Degrassi: The Next Generation (1979-2015): This is the most popular and longest-running iteration of the Degrassi franchise. It featured a large ensemble cast that changed throughout its run.
* Degrassi: The Next Generation (1979-2015): This was a spinoff of the original "Degrassi Junior High". It featured a new generation of students at the same fictional high school.
* Degrassi: Next Class (2016-2017): This was another spinoff of "Degrassi: The Next Generation" that followed a new group of students.
If you tell me the specific show you're interested in, I can provide you with the cast information.