If you wish to follow cases you can flag them.
Create a view for "Flagged cases" or "follow up cases".
Select the filter icon on the left side of the case list. Check the "Flag" checkbox.
Remember to remove agents in the Agent filter to list all open cases.
Save the new view by selecting "Save" under "Default setup"
Give the view a name, such as "Flagged cases" or "Follow up cases"
Mark cases you want in the view by checking the flag
If you want to follow cases from other agents, you can drag the "Agent" column into the group area and select cases from them.
The flagged cases will appear in your "Flagged cases" view.