What is the fine-grained topic of the following text: Carlos Ghosn, who is as of early 2018 Chairman and CEO of France-based Renault, Chairman and former CEO of Japan-based Nissan, and Chairman of Mitsubishi Motors, is typically known as the cost cutter who achieved the turnarounds at Renault, Nissan and Mitsubishi through ruthless focus on removing operational inefficiencies. Only return the topic.
Carlos Ghosn's leadership and cost-cutting strategies at Renault, Nissan, and Mitsubishi.