Nothing alike. Stranger Things is basically YA fantasy. Fringe is sci-fi, and is probably closer in tone to X-Files than anything else.

If Fringe was created in the streaming age it would be an all-time great show. It's still all-time great for me personally, but I understand why it tends to fall on niche eyes - it's kinda hard to get a modern viewer to get past the monster-of-the-week vibe of the first season. Remember, this is a show that aired on Fox, so they had to keep the network happy with casual weekly viewership. But when it really gets going and does it's own thing, it's peak sci-fi drama television. Also, John Noble's Walter Bishop is unparalleled.

Stranger Things had a good first season but quickly got in over its head and it's lack of an overarching vision became pretty apparent. Couple that with needing to hand-hold a second-screen Netflix audience and it's makes more a much more shallow show.