DPI is the mouse-side setting
DPI changes how many counts the mouse produces for a given physical movement. It is normally set in the mouse's firmware or manufacturer utility.
Sensitivity is usually a software multiplier
In games, sensitivity changes how those input counts translate into camera or aim movement. Windows and macOS also expose pointer-speed controls that affect cursor behavior.
eDPI gives a simple comparison
For many games, eDPI is calculated as DPI × in-game sensitivity. If one setup is 800 DPI at 1.0 sensitivity and another is 1600 DPI at 0.5, both have an eDPI of 800 under that game's convention.
cm/360 is even more physical
cm/360 describes how many centimeters of mouse movement are needed for a complete 360-degree turn. It is useful when comparing settings across games, although each game can use different yaw constants and input behavior.
Avoid changing multiple controls at once
If you change DPI, OS pointer speed and game sensitivity simultaneously, it becomes difficult to know which change affected your control. Change one variable at a time and document the setup.