From their origin meanings, both can means " go to somewhere". But "出“ tend to emphasis more on going from inside(or your place) to outside.
eg, when you say“ 去看电视,去上学,去买东西,去国外,去旅游...”,it means you can be anyplaces and go to do those things.
But when you say" 出国, 出差, 出门”,it means those actions are starting from your places( country, company, home..) to somewhere.