In Windows 10, the keyboard shortcut that opens Task View is Win+Tab.
Task View displays open windows and provides controls for switching between them and managing virtual desktops. Pressing the Windows key together with Tab opens the overview directly, while clicking the Task View button on the taskbar performs the same basic action.
Task View was introduced with Windows 10 and expanded the older idea of window switching. Windows 3.0 had already provided basic task switching, and Windows Vista and Windows 7 offered Flip 3D, but Task View combined a window overview with multiple desktop workspaces.
The shortcuts are easy to mix up. Alt+Tab switches among open windows, Ctrl+Tab usually changes tabs within an application, and Win+D shows or hides the desktop. Win+Tab opens the broader Task View interface rather than merely cycling through windows.