If the Chief of Staff (CoS) does not prioritize cultural integration in M&A, the risk of serious problems that could threaten the entire value of the deal increases. Common consequences are increased resistance to change, loss of key personnel, reduced productivity, and a deteriorating work environment. Cultural conflicts can lead to conflicts between teams, lack of collaboration, and integration projects taking longer than expected or failing entirely. In the worst case, this can result in the deal’s objectives – such as synergies, innovation, or market growth – never being achieved. Research shows that up to 30 % of failed integrations are due to cultural factors. Therefore, it is crucial that CoS works proactively with cultural due diligence, involves employees and management, and monitors the integration with clear KPIs and feedback.