The basic major difference between SOA and Microservice is SOA prmotes sharing the Data, whereas Microservices are promoting seperate the DB for each microservice.

SOA is a bigger concept implementing service based application where as microservice is spliting the business domain in small microservice which will communicate between each other using events( async model prefereed).

With SOA devops culture is that much popular where as with Microservice it is a kind of must to have that.

SOA is less scalable becase it has a kind of monolithic design, where microservice are more scalable as it has a differnt service for each business domain.