Task View

Task view works much like Alt-Tab in that it lets you switch between open apps and other windows. But it offers some key advantages over Alt-Tab as well: it's persistent and doesn't require the same keyboard gymnastics, it can be accessed via a handy Taskbar item, and it also lets you access Windows 11's virtual desktop feature, called Desktops.
Task view is curiously missing one key feature that's available in Alt-Tab: where Alt-Tab can be configured to display individual Microsoft Edge tabs, Task view cannot. Instead, you will see one thumbnail for Edge in Task view.
To open Task view, select the Task view item on the Taskbar.

Or, just type WINKEY + TAB.
Task view displays an Alt+Tab-like switcher at the top, with thumbnails representing each open window. But there is also a Desktops pane on the bottom for accessing any available virtual desktops or creating a new virtual desktop.

Where did it go?
In Windows 10, Task view was also home to a feature called Timeline that let you find documents and other files, websites, and other information that you had accessed in the past. It could even work across multiple PCs and devices if your data files were saved in OneDrive. However, Microsoft has discontinued this feature in Windows 11 and it is no longer available.
Desktops is a big feature that's covered by its own chapter.
Use Task view to switch between open windows
To open Task view, select the Task view item in the Taskbar.
Alternatively, type WINKEY + TAB.
Task view displays its window thumbnails a bit differently than Alt-Tab for some reason: the thumbnails are bigger and there is no visible selection box by default. But it handles the z-order similarly: the currently focused window is first in the grid of thumbnails, followed by the other most-recently-accessed windows in order.

To switch to another open window, simply select the appropriate thumbnail. Task view closes when you do so.

If you like using the keyboard, you can use the RIGHT ARROW and LEFT ARROW keys to navigate through the available open windows in order. You will even see a selection box appear when you do so. Type ENTER or SPACE to switch to the selected window.
Remove the Task view item from the Taskbar
Task view is a useful feature and, unlike with Alt-Tab, it's discoverable because Microsoft places a Task view button on the Taskbar. But the Task view item is largely unnecessary if you know Task view's keyboard shortcut, WINKEY + TAB. So you can safely remove it to free up space on your Taskbar.

To do so, right-click an empty area of the Taskbar and choose "Taskbar settings" from the context menu that appears. (It's the only choice.) The Settings app opens to Personalization > Taskbar.

Toggle the Task view setting under Taskbar items to Off to hide the Task view item.