Lenovo ThinkVision P40w-20 39.7" 5K Ultrawide Curved Monitor - Manual (Page 13)

Chapter 1 Get started with your monitor 1-9
PbP
The PbP (Picture-by-Picture) function make the monitor to display two different video sources
simultaneously. User can select any one of 3 inputs (DP, HDMI, Thunderbolt) for the left screen, select
another input for the right one.
For example, the left screen PC1 could be input of DisplayPort, HDMI or Thunderbolt notebook, the
right screen PC2 would be rest input.
The Layout of PbP is always 5:5 of which is for the best experience and highest working efficiency, best
resolution for each sub-screen is 2560x2160@60hz.
PiP
As same to PbP, the PiP (Picture-in-Picture) function can receive two different video sources too.
The best resolution of foreground PC2 is 1920x1080@60hz.
The foreground PC2 sub-screen can be placed on top left, top right, bottom left, bottom right of monitor.