Spitzenkandidat
The Spitzenkandidat is the named politician leading a political party’s candidate list in an electoral system using proportional representation. See pertinent Politico article from 2015 and State of the European Union address analysis here. The EU’s introduction of named leaders to European-wide elections required a precise word to describe the role, and German is the largest EU member and has a proportional representation election process, so provides a term which is lacking in English, particularly given the UK’s crippling lack of proportional representation systems.