By using split view in Salesforce Lightning, we can see a list view and a record side by side. To move on to a new record, select it from the split view in Salesforce Lightning, and the new record opens with the list still in view. No more navigating back and forth between list and records. Split view is great for going through records in sequence or for quickly skimming through a set of records.

The split view panel is collapsible for extra flexibility.

When can Have Split View Lightning Experience in Group, Essentials, Professional, Enterprise, Performance, Unlimited, and Developer editions.

Let’s see how to Create and use the list view in salesforce lightning in account object.

Step-1 : Go to Any one of the list view in salesforce lightning. Here we have selected Account List view.

Step-2 : After that Select Split View from the dropdown menu as we mentioned below screenshot.

Step-3: After Selecting the Split View, below would be the page view.

Step-4 : Click any one of the record from left side of the panel. We can able to see that record details in right side.

Step-5 : We can able to hide and unhide the split in current page by click the Collapse Arrow(Refer in Screenshot).

Step-6 : After click Collapse.

Step-7 : We can re-click  to expand the list again.

Source :
Summar Release 20

Additional List View:
How to Create the Kanban list view in Salesforce Lightning

How to Create List View in Salesforce Lightning