She later worked for a time at a law firm, as well as a 8-year spell at the Provincial Deputation of Zaragoza.

[1][2] She ran as PSOE senatorial candidate for the province of Zaragoza vis-à-vis the 2008 general election; Sumelzo was elected and she served as member of the Upper House for its 8th term integrated within the Socialist Parliamentary Group.

[3] Regarding the 2011 general election, she ran in the PSOE list for Zaragoza for the Congress of Deputies.

[4] Once Pedro Sánchez made a comeback to party leadership, Sumelzo joined the PSOE's Federal Executive Board in June 2017, charged with responsibilities at the Area of Municipal Politics.

[6] In addition to her committee assignments, Sumelzo has been a member of the Spanish delegation to the Parliamentary Assembly of the Council of Europe (PACE) since 2019.