Apart from the fact that the Samsung Z1 (2016) could sport an AMOLED display, there's no word on what features it's supposed to be bringing. In any case, just like the Z1 from last year, the new model is, most probably, an entry-level device made for customers who can't really afford to pay too much for a new handset. At launch, the original Z1 - pictured below - was sold for around $90, and we assume that its successor will be offered for a similar price.
The original Z1 and the Z3 haven't been released in the US, but maybe Samsung is planning to bring the new Z1 (2016), or another Tizen smartphone, to North America at some point. We'll definitely let you know if that happens.