For most professional roles, what must an employer often prove before sponsoring a foreign national for a work visa?

Answer

They could not find a suitable local candidate

The hiring company frequently needs to demonstrate that they exhausted the local labor pool and could not find a suitable local candidate before they are allowed to sponsor a foreign national for a work visa.

For most professional roles, what must an employer often prove before sponsoring a foreign national for a work visa?
jobvisaemigrationrequirement