The coming years will bring new large data sets at various wavelengths of the electromagnetic spectrum, accompanied by a new window due to the discovery of gravitational waves. Dedicated projects and generally oriented space and ground-based observatories will allow to make the distance measurements with current well developed methods more precise, and the new emerging methods have a chance to reach maturity. Large data sets will push the statistical errors down significantly, so the possible systematic biases will become more important. Improvements within a given method will be crucial, but the key tests will lie in cross-check of the results based on independent methods. From this point of view, new emerging methods are as important as the further increase in the already impressive accuracy achieved with the use of SN Ia.
Acknowledgements BCZ was supported by the NCN grant 2015/17/B/ST9/03436 and a Fellowship from the Chinese Academy of Sciences, and acknowledges being a part of the network supported by the COST Action TD1403 Big Data Era in Sky and Earth Observation. MB was partially supported by the NCN grants UMO-2014/14/M/ST9/00707, UMO-2013/01/ASPERA/ST9/00001 and the COST Action MP1304 "NewCompStar". RFIH was supported by Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq). SWJ acknowledges support from NASA/Keck JPL RSA 1508337 and Department of Energy award DE-SC0011636. JJ gratefully acknowledges the support of NASA grant GO-14219.003-A. E.L. is supported by a European Union COFUND/Durham Junior Research Fellowship (under EU grant agreement no. 609412). MDO acknowledges partial support by the PRIN-INAF 2014, "Transient Universe: unveiling new types of stellar explosions with PESSTO" (P.I.: A. Pastorello). We thank ISSI-BJ for hospitality and an engaging workshop.