Yes, there is a limit to the number of branches deep that you can go in any given branch. That limit is 15 if/then branches deep.
What does it mean to go X branches deep? The "depth level" of the branch is the amount of branches a contact would need to meet before ending up at that branch.
The first branch you see has depth level 1, the next 2, and so on:
If you attempt to add an 11th branch, you will be able to add the branch, but will see a warning.
You will be able to add up to 15 if/then branches.
If you need to remove if/then branches from the workflow because you are reaching this limit, it is recommended you remove them from the bottom of the workflow. You can also create a new workflow with those actions and branches and enroll the contacts from this workflow in the new workflow.