Legal immigration is a mixed bag. It has pros and cons. It increases the supply of labor, which decreases average money wage rates, but it expands the division of labor which increases productivity of labor, which increases average real wage rates.
To the US worker( or any worker in any country for that matter) there is no benefit to immigration. It is burden to the taxpayer and the wage earner alike. Most immigrants use welfare/social services and when/if they finally do get citizenship are way more Likely to vote Democrat. It is lose - lose - lose..