I'm guessing that your question is about physical and chemical exfoliating cleansers?
If that's the case, physical exfoliating cleansers/scrubs contain particles that literally scrub the skin and can often damage the skin by creating micro-tears.
Chemical exfoliating cleansers contain AHA and/or BHA acids that clean the pores and the help remove the dead skin cells.
To sum up, if you need exfoliation, always better to go for a chemical exfoliant.