Only exception is if you're a DO student, you are not required to take the USMLE in order to obtain a license to practice. A DO student HAS to take the COMLEX in order to obtain a license to practice.
Yes Everyone who chooses to practice medicine in the USA, must have a medical degree, take and pass step1,step2cs,step2ck,step3 and must have finished a residency program. Good luck through your process