This dissertation is comprised of three essays that examine how migration policies, especially in the context of globalization, influence immigrants' migration decisions, and what effects immigrants may have on natives and the local economy. In the first two chapters, I demonstrate the importance of studying migration policies in a comparative framework. In Chapter 1, I focus on the comparative immigration policies for international students in the U.K. and the U.S. I examine the causal effect of international student enrollment on college completion of U.S. domestic students by leveraging a restrictive immigration policy change in the U.K. that induced more international students from former British colonies to enroll in U.S. universities. Using newly obtained administrative data on all international students in the U.S. between 2003 and 2015, I find that an additional international student per program leads to 0.7 more domestic students to obtain a college degree four years later. The effect is concentrated in public four-year institutions. Additionally, I find positive cross-degree-level effect of international students in master's degree programs on U.S. domestic students in bachelor's degree programs. The positive impact is most likely through cross-subsidization of tuition, serving as evidence of resource effects. In Chapter 2, I focus on the comparative immigration policies for high-skilled immigrants in the U.S. and Canada. The current U.S. immigration quota system that imposes limits on the number of green cards based on nationalities has not changed since 1991, while demand has increased exponentially. This results in long wait times for individuals from high demand countries. For employment-based green cards, in recent years, college-educated workers from India need to wait for over a decade before submitting applications. In contrast, Canada has implemented several favorable immigration policies to attract high-skilled immigrants. I examine the effect of this immigration policy gap on immigrant inflows and labor market outcomes in Canada. I first show that the adoption of Express Entry, Canada's point-based immigration program, significantly increases new economic immigrants from India. I then estimate the labor market impact of new immigrants using an instrumental variable strategy. Results show that the surge of new immigrants does not negatively affect employment in local labor markets. In Chapter 3, my coauthors and I examine the effect of 287(g) on employment in large firms, separately for Hispanic and white workers. Using the data on county-level 287(g) applications and establishment-level employee data from the Equal Employment Opportunity Commission, we employ a difference-in-differences identification strategy, comparing employment outcomes of establishments in 287(g) implemented counties to those in 287(g) denied counties, before and after the implementation of 287(g). Overall, we find that 287(g) has significant and negative impacts on both Hispanic and white employment. The effects are concentrated in a few selected industries; for Hispanic workers, agriculture and mining, health care/social services, and accommodation/food services suffer the largest negative impacts, while for white workers, the adverse employment effects are mostly concentrated in wholesale and retail trade, as well as in administrative support/waste management and the health sectors. We also find that 287(g) differentially affects Hispanic and white workers by gender. For Hispanic workers, most of the effects are driven by male employment, consistent with the fact that deportation in the interior U.S. disproportionately impacts Hispanic men more than Hispanic women. For white workers, on the contrary, both male and female employment are negatively and statistically significantly affected by the implementation of 287(g).