In April 2018, he was named in Uganda's squad for the 2018 ICC World Cricket League Division Four tournament in Malaysia.
[4] In July 2018, he was part of Uganda's squad in the Eastern sub region group for the 2018–19 ICC World Twenty20 Africa Qualifier tournament.
[6][7] The following month, he was named in Uganda's squad for the 2018 ICC World Cricket League Division Three tournament in Oman.
[12] On 15 February 2020, in the third and final match against Qatar, Muhumuza became the first bowler for Uganda to take a five-wicket haul in T20I cricket.
[13] In November 2021, he was named as the vice-captain of Uganda's squad for the Regional Final of the 2021 ICC Men's T20 World Cup Africa Qualifier tournament in Rwanda.