Answer:
From the American worker perspective
Benefit: outsourcing reduces costs for American and foreign firms, and this cost reduction is translated into cheaper goods that are imported to the U.S. These cheaper goods means that the American workers can buy more things with the same income. In other words, the real wage of the American workers increases thanks to outsourcing.
Cost: outsourcing causes job loses in the firms and sectors that engage in it. For some people, outsourcing can result in unemployment for months, even years.
From the foreign worker perspective
Benefit: foreign workers get to work at companies established by American capital, opening up opportunities that with domestic capital only, may not have been possible in first place.
Cost: the American companies in the foreign country may be too competitive for domestic companies. Foreign workers may find it harder transition to start their own businesses due to the new American competition.