Previous measurements of the ratio of semileptonic decays π (π·β)=π΅(π΅βπ·βtau nu)/π΅(π΅βπ·β mu nu) and π (π·0)=π΅(π΅βπ·0 tau nu)/π΅(π΅βπ·0 mu nu) from Babar, Belle, and LHCb hint at a deviation from lepton universality. This colloquium presents the first joint measurement of both π (π·β) and π (π·0) at LHCb, reconstructed with the tauβmu nu nubar decay mode in the [π·β mu] and [π·0 mu] final states and assuming isospin symmetry. This pathfinder analysis is based on Run 1 data. This result supersedes the previous LHCb measurement of π (π·(β+)) alone with the muonic decay of the tau.