I found Fringe to be a pretty faithful “sequel” to the X-Files.
I never was quite into the x-files as all it seemed to do was portray Mulder and Scully as being perpetually unable to outmaneuver any of their higher-up opponents. Cases would be “solved”, and then put away, but the schemers behind the scenes were never outed or made to pay a price for their manipulations.
I think the series “Continuum” was quite interesting, however -if not like the x-files at all. “12 Monkeys” is getting quite good as well.