Care to link that trailer? Since i looked it up and it has ESRB Teen (T) rating, not Mature 17+ (M) rating.
Early reveal trailer, 10 months before release:
Here’s what those ratings also stand for:
Content is generally suitable for ages 13 and up. May contain violence, suggestive themes, crude humor, minimal blood, simulated gambling and/or infrequent use of strong language.
Content is generally suitable for ages 17 and up. May contain intense violence, blood and gore, sexual content and/or strong language.
source: Ratings Guides, Categories, Content Descriptors | ESRB Ratings
Video games that show violence of a slightly more graphic nature towards fantasy characters or non-realistic violence towards human-like characters would fall in this age category. Sexual innuendo or sexual posturing can be present, while any bad language in this category must be mild.
This rating is applied once the depiction of violence (or sexual activity) reaches a stage that looks the same as would be expected in real life. The use of bad language in games with a PEGI 16 rating can be more extreme, while the use of tobacco, alcohol or illegal drugs can also be present.
Source: What do the labels mean? | Pegi Public Site