The new Timeline Associated Record feature is great. I noticed that you can go into Renewal Center and create a Timeline entry on an Opportunity and associate it to a CTA.
You cannot though, create a Timeline entry from the global timeline or C360 timeline (or CTA timeline for that matter) and associate it with an Opportunity. Even if it is for the same company.
If you can do it one way it would be great to be able to have it bidirectional!