I congratulate you on your new role and wish you all the best in your work.
'Congratulo' = con-GRA-tu-lo; stress on the second syllable.
Use to congratulate a professional contact on a new appointment, promotion, or career milestone.
'La congratulo' is the formal way to congratulate someone (the reflexive 'mi congratulo con lei' is also correct). 'Buon lavoro' (good work/all the best in your work) is a characteristic Italian phrase used as a well-wish when someone starts something new.
Mi congratulo con lei per la promozione.
I congratulate you on your promotion.
Reflexive form; equally correct and common
Tanti auguri per il nuovo ruolo!
Best wishes for the new role!
Warmer and more informal
Sono lieto/a di apprendere della sua nomina.
I am pleased to learn of your appointment.
References the specific type of new role
Italians value personal touch in professional relationships. Congratulating a contact on a new role — even with a brief email — builds goodwill and keeps the professional network active. LinkedIn is widely used in Italy for this purpose too.