Modern retention strategies. What actually matters?

Every now and then I’m doing a research on what’s the most valuable benefits for employees that the company can offer.
TOP 3 are mostly the same year to year: compensation, growth opportunities, flexibility. Of course details vary based on the domain, location, etc. but we can see the trends pretty clear.
Working now on the Retention strategy I wonder, if there’s a key to employees satisfaction?
I would like to ask you, dear colleges, to share your experience and real cases on what benefits actually made a difference for your teams?