Basic Trope: A person who had a high-paying/prestigious job in another country does menial work in the setting of the work.
Straight: Bob worked as a doctor in Troperistan, but works as a janitor in Troperia.
Bob was the CEO of a Fiction 500 company based in Troperistan, but works as a janitor in Troperia.
Bob has multiple PhDs from Troperistan but can only get work as a janitor in Troperia.
Downplayed: Bob worked as a doctor in Troperistan, but can only find work as a medical assistant in Troperia.
Bob's Troperistanian qualifications and certificates aren't recognized by Troperian hospitals for various reasons.
Bob doesn't speak Troperian very well, if at all.
Employers suspect that diploma mills may be using 'foreign' degrees as a cover.
Troperia has a shortage of doctors and government policy there is to hire native-born Troperian students first.
Or, conversely, Troperia has too many doctors and as such there just isn't room for Bob.
The quality of medical training (or education in general) in Troperistan is considered sub-par by Troperian standards, so Bob's qualifications and experience carry little weight with recruiters.
Inverted: Bob was a lowly janitor in Troperistan, but when he arrives in Troperia, he's offered a job as a doctor.
Subverted: The chief of medicine at the hospital where Bob is applying to work acts as if he's going to reject Bob, but hires him.
Double Subverted: The chief of medicine at the hospital where Bob is applying to work acts as if he's going to reject Bob, but hires him... as a janitor.
Parodied: All the janitors at the hospital have prestigious medical degrees from foreign countries.
Zig Zagged: Bob was a doctor in Troperistan, but can only find menial work as a janitor in Troperia. Alice, on the other hand, was a short-order cook from Troperistan who got a high-paying systems analyst job in Troperia. Charlie, a third immigrant from Troperistan, worked with Bob at their old hospital, and fills a similar job as a surgeon in Troperia.
Averted: Bob, a doctor from Troperistan, finds a similar job as a doctor in Troperia.
Enforced: In a time of widespread xenophobia, the writers can't write a competent and ethically scrupulous foreign character without mass backlash.
Lampshaded: "I had dignified work back home!"
Invoked: "Hey, let's ask Bob the janitor. I'll bet he was a doctor back in Troperistan."
Exploited: Bob the janitor may not be officially recognized as a doctor, but Bob still has the skills of a doctor and people go to see him instead of 'real' doctors because he gives cheap 'advice' and they give him monetary 'gifts'. Totally not practising medicine without a licence at all.
Defied: Bob goes to medical school in Troperia at the first opportunity so that he can keep up his rewarding career.