These are the jobs from which Americans are disappearing due to H1-B visas. Cruz wants 500,000 MORE H1-B visas, to finish off Americans getting STEM jobs (for which there are hundreds of thousands Americans qualified, either by experience, education, or both.)
These are the jobs the corporation requires the American employee being booted to TRAIN his Indian replacement on. If the American refuses, he loses his severance and possibly his pension.