James Sanderson, who founded Wunderman Thompson Inside, joins Havas Studios from marketing consultancy ICP.
Industry veteran Michael Karg joins agency's global leadership team.
He emerges as contender to succeed John Wren.
He will continue existing responsibilities as EMEA chief executive, but plans to spend much time on APAC and the US.
ByteDance took another step on its globalisation process by hiring Disney-veteran Kevin Mayer for operation.
The COO will focus on the network's four major areas of creative, media, CRM and brand.
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