[1] She holds several positions related to European integration, including deputy chairperson of the Committee on Ukraine's Integration into the European Union (as of 2020[update])[2] and chairperson of the Ukrainian delegation to the Parliamentary Assembly of the Council of Europe (as of 2021[update]).

[2] As of 2021[update], she was the chairperson of the Ukrainian delegation to the Parliamentary Assembly of the Council of Europe (PACE).

[3][4] In November 2021, Mezentseva saw priorities for Ukraine in the Council of Europe (COE) to include "democracy and human rights, vaccination and the environment, sustainable development and displaced persons".

Mezentseva stated that the Ukrainian delegation filed a complaint under the PACE Code of Conduct.

She described herself as "a young person who does not represent particular international companies or organizations, having limited financial resources to campaign", and saw that as a sign that Ukraine democracy was developing positively.