This is big salary level, I take it? $250K plus?
Has candidate spoken with grad school contacts (school and friends)?
Has candidate tried to become a thought leader/commentator in the field?
Sometimes old hands reinvent themselves by getting involved with startups. What companies used to market to the candidate? Try joining the ecosystem around VPs of HR.
I really like the Hebba Youssef "I Hate it Here" blog/podcast. Maybe see if there is a story to pitch to her?
https://hateithere.co/