When a process is sent for approval, it shows up in the approvers dashboard. To see who has/hasn't approved it, you need to place your mouse over the person icon.
This isn't intuitive and is missed by most people and is one of the more common queries I get from experts and owners.
If this icon had a header (like the rest of the fields) this would help draw attention to it. There also might be a better way of displaying this, such as a count or percentage of approvals completed. Or a series of checkboxes that show approval vs decline vs pending (see image for rough concept).