Neither will lose their place on the battlefield, not until the entire battlefields are completely unmanned and every meter is covered by AD. Tanks are necessary to provide cover, fire support and hunt other armour, and drones are useful for reconnaissance and strike on targets of opportunity at worst and proper targets at best with stand off munitions.
I do expect changes in both tanks and drones, or rather a more distinct separation than we have today, the same way there used to be light and heavy tanks before main battle tanks became the norm as a compromise between different needs.