Slavery has had a long and storied history in America, many people believing that it is dead and buried, perhaps ending with Lincoln's Emancipation Proclamation of January 1, 1863, or perhaps believing that slavery was really over after the passage of the Thirteenth through the Fifteenth Amendments soon after the Civil War, or for some people, perhaps the seminal moment when we knew that slavery and the vestiges of slavery was eradicated from America, was when the Civil Rights Act of 1964 was passed. Unfortunately, despite all the progress that America has made against slavery over the last two hundred odd years, slavery still exists in America, but has morphed into something that has adjusted with the times, and those that are treated as modern-day slaves in today's America, aren't typically black or African in their heritage, but Hispanics, primarily from Mexico, or from Central America, Spanish speaking, and typically seen by the law, authorities, and employment agencies, as illegal aliens to be exploited.
For Hispanics in America, there is a huge dividing line, between Hispanics that have already been assimilated, normalized, or native-born, and the like, as compared to those that are most definitely illegal border jumpers, in debt to "coyotes", poorly educated and/or functionally illiterate, have poor English language skills, and often hold forged or makeshift documents to identify themselves. As you might expect, in a country built around a capitalistic footprint, which is also often highly competitive in select industries, and recognizing too that the cost of labor, health care, and the training of employees will make an appreciable difference in the profitability of said company, therefore there are explicit as well as implicit reasons why certain companies are overjoyed to have a segment of the labor force that is susceptible to giving in to the demands of management and consequently excellent subjects for labor exploitation.
While some may argue that illegal aliens can't be considered to be slaves, simply because they voluntarily cross the border into our sovereign nation, this is a very mistaken notion. For instance, who but illegal Hispanics, as agricultural workers, for example, are subject as a matter of course, of being not paid a fair wage for their labor, or of being paid less that contracted for or nothing at all because they that "employ" them recognize that Hispanics when it comes to the payment of a wage have little or no power to fight back, and further that Hispanics can be charged essentially whatever management wants to charge them for room and board, tools, food, water, and also to subtract from their wages any damages or product loss that may have occurred.
Illegal aliens are exploited in America, day in and day out, because the exploitation is at best, in that "gray area" of the law and employment, and at worse, outright thievery. While some may decry the sheer numbers of illegal immigrants in America, those in the know, embrace them, because their very business model depends on cheap, replaceable, and exploitable labor. The real reason behind why there is such a huge inflow of modern-day slaves into America is because there is profit in it, enough profit to spread it around so that those that could stop it, don't; and those that rely on it, get what they need.