Mbumba has 30 years of media experience and is currently the CEO of Nation Publication in Malawi. Among her previous roles was the head  of Sales and Marketing for Xerographics Malawi from 1989 to1992. In 1993, she co-founded Nation Publications Ltd and have been CEO since. Under her leadership, Nation has evolved from a tri-weekly newspaper to a daily publication. They have also expanded their digital presence with a website, e-paper, and active social media channels. In addition to media, they offer commercial printing and are exploring new revenue streams. To manage their flagship CSR projects, they are setting up a Trust which will at the same time promotes social enterprise ventures.