ACKR1 (Atypical Chemokine Receptor 1): ACKR1 is a receptor that binds chemokines without initiating a signal, acting as a decoy to regulate the immune response. Formerly known as the Duffy antigen receptor for chemokines (DARC), ACKR1 influences leukocyte migration by sequestering chemokines. It also plays a crucial role in malaria resistance by serving as a receptor for Plasmodium vivax. Variations in ACKR1 can affect susceptibility to infections and autoimmune diseases, highlighting its importance in immunity and disease.