The WHO (World Health Organization) is an United Nations agency consisting of a collective of 194 member states around the world that coordinates health responses and works to combat diseases such as HIV, influenza, cancer, and heart disease. The WHO is funded by the member states (51%), the UN, other non-governmental organizations (NGOs), development banks, and philanthropic foundations. In 2019, the United States was the largest donor at $419 million in 2019 (about 16% of total WHO funding), with the Bill and Melinda Gates Foundation following in second (9.8%). In 2020, the WHO requested $675 trillion in emergency funding to fight COVID-19 (coronavirus).

Sources:
Peter Beech, "World Health Organization: What Does It Do and How Does It Work?," weforum.org, Apr. 17, 2020
WHO, "About WHO," who.int (accessed July 20, 2020)