Volume-regulated anion channels (VRACs) are present in vertebrate cells and a variety of tumor cells. VRACs include leucine-rich-repeat-containing 8A (LRRC8A) and its four homologous family members (LRRC8B-E), of which LRRC8A is an essential subunit. It has been confirmed that the VRAC LRRC8A is involved in the proliferation, migration, invasion, and multi-drug resistance of tumor cells through various signaling pathways. This ion transporter has shown good potential for use in strategies to kill tumor cells and prevent the development of tumors and can be used as a new target for tumor therapy. Therefore, this paper reviews the latest research on the involvement of LRRC8A in tumorigenesis and development. The molecular structure, function, and regulation of LRRC8A in tumor and immune cells, with emphasis on targeting LRRC8A in tumor diagnosis and immunotherapy, are discussed, providing a reference for studies exploring LRRC8A as a new tumor therapy target.