In early March 2019 Sánchez Mato announced his intention to run in the IU primaries to select its candidates to the April 2019 general election in the Madrid constituency within the Unidas Podemos coalition list. Four days later he dropped his candidacy, thinking in what was "best for the project". Following the renouncement of Mauricio Valiente to led IU in the primary election of the Madrid En Pie coalition for the list to be presented at the 2019 Madrid municipal election, after the membership of United Left–Madrid (IU–Madrid) decided in a referendum not to run in the Unidas Podemos coalition for the 2019 Madrilenian regional election (in collision with the federal board's stance), Sánchez Mato accepted the responsibility of replacing Valiente on the condition the IU board tried their best to finally include Podemos in some form in the regional tentative candidacy, then visibly led by Sol Sánchez (IU–Madrid) and Raúl Camargo (Anticapitalistas Madrid). He edged Rommy Arce and Pablo Carmona in the voting to select the head of the municipal list.