An updated theoretical scenario for Cepheids, RR Lyrae and Type II Cepheids in the Rubin-LSST filters, has recently been developed. The derived metal dependent Period-Luminosity and Period-Wesenheit relations can be used to infer distances or be inverted to infer the metallicity distribution. Furthermore, the individual star properties and distances can be inferred by directly comparing the observational data with the predicted multi-filter light curves and pulsational velocity fluctuations. A recently published application to Gaia data is presented to show the method and the expected results. The perspectives of application to Rubin-LSST time-series data for Cepheids, RR Lyrae and Type II Cepheids are finally discussed.