Welcome, Dadadino.
There's no one trailer associated with a movie. IMDb hosts trailers and also provides a page of links to external trailers. So if what you want is one link to a representative trailer for each movie, the problem is to devise a means to choose the best link. But regardless, the links are normally (if not always) to a web page where the trailer is hosted. If you have to play the trailer in a browser anyway, you may as well just go to the /videosites page and choose a link. You can also create Web Searches to link to your favourite trailer sites.
Note that IMDb seems to be in the process of changing how videos are handled (probably to favour those they are hosting over external sites). Problem is, the /trailers pages the links point to have nothing on them. It seems you have to manually append /videosites to the URL to get to the "Videos and Trailers" page.
