I am writing to share a doubt I have.

I have to compare two datasets with 352 entries. One of them has gaussian (normal) distribution and the other an unknown distribution. When I look at both histograms distributions, they are superimposed, and visually there is no statistical significance between the means and medians. However, running a Wilcoxon rank-sum test (matlab), I discovered there is a statistical significance that seems to be counterintuitive. Must I use another test to compare the datasets? I tried t-test too and I got a similar result. Somebody could give me some tips?

Tks in advance