immigration via work opportunities

hello everyone, from the people i know to the discourse online the majority of people who go abroad do so either via immigration programs like express entry or the greencard lottery or by going as foreign student and getting a degree, but whenever i look at official websites there are always work options, in the sense that you could land a job before even stepping foot in the country and getting a work visa and then after a few years getting residency or smth, but ive literaly never heard of it happening to somebody, is it a reaal thing ? or is it just in specific fields like medicine ? i have a master's in biology ( specialized in genetics) so supposedly with my master's i could find a job abroad before even moving there ? it can't be that easy right ? though if anyone has a personal experience like that i would love to hear it