Democrats: Leon Panetta, Susan Rice, Janet Yellen, Hillary Clinton, Joe Biden, Robert Reich, Eric Holder...
Republicans: George HW Bush, Rice, Rumsfeld, Cheney, Powell, Ashcroft, Baker, Gates...
It shouldn't intuitively surprise you that people normally work in lower level administration roles before being appointed to cabinet secretary or running for VP.
Trump wanted to get new blood even in his first term and then took it upon himself to purge the GOP after McCain's nay vote re: ACA repeal. It'll be interesting to see if that old guard comes back after Trump's term, especially after they endorsed Harris for president last election cycle.