Believe it or not, there are frum people that work for the Mossad.
Some even at the operatiave level.
However there is the famous story of an agent who was recommended for an extended mission in an enemy country. He asked R’Sholomo Zalman Auerbach if he should go as he would have to abandom mitzvots as any marker no matter how small would put him in danager.
R’Shlomo said that if it’s a mission that can save Jewish lives then it is proper for him to go and likened it to when Esther lived in Achashveroses palace in order to save her people. He said the lack of mitzvots could be rectified after the mission and was a temprorary situation. He went on to say that the nature of espionage is that you must be ready to kill at any moment and the violence can force you to be desensitized to the point where you can kill someone and then order a cup of coffee as if it was just another errand to run that day. R’Shlomo Zalman said, that kind of damage can not be undone and therefore it was not proper for him to take the assignment.