Considerations for the Timeline and Activity Related Lists | Salesforce
Considerations for the Timeline and Activity Related Lists
On the detail page for objects that support activities, Lightning Experience doesn’t display the Open Activities and Activity History related lists along with other related lists. It displays the activity timeline instead. Objects that support activities include opportunities, leads, accounts, contacts, contracts, and custom objects on which you enable activities.
Available in Lightning Experience in: Professional, Enterprise, Performance, Unlimited, and Developer Editions