Genome-wide association studies (GWAS) have revolutionized our understanding of the CCR5 gene’s significance in HIV-1 infections. CCR5 is a key genetic factor that influences the course of HIV-1 infections by modifying the presence of its coreceptor on immune cells. Homozygosity for a specific CCR5 mutation grants resistance to HIV-1, while heterozygosity leads to delayed progression of the disease. GWAS played a pivotal role in these discoveries, leading to the development of CCR5-blocking antiretroviral therapies. This review underscores the essential role of GWAS in crafting therapeutic strategies for viral infectious diseases, particularly HIV-1.