What did the american southwest have that attracted people from mexico to the area?

Economic opportunities in the southwest, including large extensions of land for cattle raising  attracted people from mexico to the area.

Beginning around the 1890s, new industries in the U.S. Southwest—especially mining and agriculture—attracted Mexican migrant laborers. Mexicans moved to the American southwest to work on farms, mines, and factories since thet were in the pursuit of better economic opportunities to have better lives.

Besides, the Mexican Revolution (1910-1920) also encouraged migration to the southwest.