Start from how your team already works

Product teams

A roadmap that survives contact with a shipping date, because the roadmap and the tickets are the same records. Moving a date moves the thing the date was attached to.

Marketing teams

A campaign calendar with the assets attached to the dates, so the question "what is going out on Thursday" has one answer rather than three.

Operations teams

Recurring work that does not depend on anyone remembering it, and a record of what happened the last forty times it ran.

Engineering teams

Incidents that leave a written trail without anyone writing a report. The timeline is assembled from the record, not from memory.