It's technically proper Latin, and it's use in English is archaic outside of academia. For the most part IRL people just say "slash". The only time I've ever seen anyone use A-cum-B (again outside of specific Latin terms in academia, some I occasionally use myself) is in translated web novels/manhuas since there aren't many better alternatives.
That said I don't know how "slash" would sound to anyone outside of American English so I'm not going to propose it as a solution without a slew of opinions from other English dialects. Though simply writing "A/B" would allow the reader to fill in the blanks themselves.