[3] [4] During this time in Namibia, Muyumba served as the acting country coordinator of the United Nations Association.

[7] The PYU functions as the elected representative body for all African youth (defined as those under 35 years of age)—a demographic that consists of 65 percent of Africa's population.

[8] During her tenure as president of the PYU, Muyumba strengthened the relationship with the African Union Commission, in order to bring African youth to the center of decision making; and facilitated intergenerational communication and the inclusion of youth voices in political matters across Africa.

Muyumba worked with the African Union chairwoman Nkosazana Dlamini-Zuma to establish continental youth development funds.

[12] Muyumba is a frequent presenter in international youth and women's forums; in 2015, Muyumba spoke at the Global Summit of Women in São Paulo, the United Nations General Assembly, the first World Youth Forum on peace and security in Amman, the African Union Heads of State and government summits, and the Millennium Campus Conference at the United Nations.

In July 2019, she married long time partner and spokesperson of Congo's former ruling party, Patrick Nkanga, in a traditional wedding in Kinshasa.