One can always be a lawyer and also avoid halachic issues, but as is often the case in many professions, respecting halacha will come with a price. Some types of legal work are clearly against halacha (e.g. assisting someone in a divorce in extorting money from the ex-spouse by refusing to give a “get” as ordered by Beis Din). Others are murky (convicting the innocent and acquitting the guilty in criminal cases). — The same is true in other professions. Just because you are a doctor doesn’t mean you have to perform (“elective”) abortions. Just because you work in the corporate world doesn’t mean you have to be an insider trader. Just because you are a professional athlete doesn’t mean you have to take prohibitted drugs. Just because you run a kosher restaurant doesn’t mean you have to compromise on kashruth. However in general, it is more profitable to be cheat than be honest – in any profession.
If you are entering law since the subject is interesting, you can find honest work and a respectable living. If you are entering law since you think it is an easy way to get rich, you will be miserable and be sorely tempted to cheat.