Walmart employees receive $6.2 billion in means tested public assistance each year, because they aren't paid enough. This is a very direct subsidy of a highly profitable corporation's bad labor practices. (For what it is worth, Walmart is not, however, among the big U.S. businesses that pay only a small share of its profits in corporate income taxes, although it received a huge tax cut when corporate tax rates were dramatically lowered starting in the 2018 calendar year that almost entirely benefitted shareholders and senior executives of the corporations receiving tax cuts.)
In contrast, undocumented immigrants have been repeatedly shown to pay far more in taxes (including taxes such as sales taxes, property taxes and withholding taxes) than they receive in government benefits. The only significant form of means tested assistance received by undocumented immigrants is Medicaid assistance with paying for the births of their U.S. citizen children.