Abstract: The concept of LEMMA uses a positron beam of about 45 GeV interacting on electrons on target. We will discuss the challenges, future plans and prospects of this proposal. We will present the accelerator scheme, with the optics and beam dynamics performed so far on the positron and muon beams. We will describe the challenges on the muon production target for a Multi-TeV muon collider in the 10^35 cm^-2 s^-1 luminosity range. An experimental program aiming to study the features of the process e+e- -> mu+mu- close to the production threshold, by using a positron beam of energy greater than 44 GeV on a solid target, is ongoing at the SPS CERN facility. The main goals are the precise measurement of the muon pair production rate and the emittance of the produced beam as a function of the center-of-mass energy and for different kind of targets. A summary of the 2018 beam test and the perspectives of the test beam planned for 2022 with an improved experimental setup will be presented.