Boeing delivered in March the third and last KC-135E STRATOTANKER to Chile. Before that all aircraft completed Programmed Depot Maintenance and they are rented out by the USAF. The KC-135E should provide an affordable interim or long term solution for countries with tanker requirements. Boeing is expecting the second hand market for such airplanes as huge.
The KC-135 will be operated by the USAF until 2040+. And this week, Boeing is expecting talks with Chile about expanding the fleet.
The follow up of the KC-135 will be the KC-46, but this “second hand” solution is an opportunity for countries with tight budgets.