What’s so good about becoming an immigration lawyer?
and what kind of jobs can you get with a law degree specializing in immigration
What is so good about it? The money 
Immigration lawyer or attorney is a good career path if you want a steady income. There will probably never be a shortage of people wanting to immigrate, get work permits, tourist visas, or just fix up their bad status. You probably should do it because you have compassion for people first (or if on the other side of the fence, a total lack thereof)
It’s a long and mostly thankless job that will have you running across town to meet deadlines, submit paperwork, and a whole host of other irritations that crop up on a daily basis.
FAIR Lawyer Gives Civil Rights Hearing Statement
