The appointments follow the arrival of new chief executive Cindy Rose on 1 September.
Dentsu is reported to be exploring divestment options including sale of a minority stake to a full sale of its overseas operations.
The tech company has worked with Accenture Song before on the creative side.
Baiju Shah replaces founder Ajaz Ahmed, who left in October 2024.
Analysts assessed whether further downgrades will be a broader industry issue.
Five of Campaign's global editors spoke on a panel at Campaign House in Cannes.
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