Dire circumstances led the X-Men to join forces with the Brotherhood to save mutantkind from those that hated and feared them.

Source: https://www.cbr.com/every-pre-mcu-marvel-movie-chronologically/

In fact, since Orchis' attack on mutantkind during the last Hellfire Gala, Gambit has gone above and beyond to prove just how devoted to the cause he truly is.

Source: https://www.cbr.com/x-men-gambit-controversial-marvel/

The few who remain have dedicated themselves to fighting the very evil that wiped out mutantkind, the evil organization Orchis.

Source: https://screenrant.com/xmen-insults-thor-children-of-the-vault-preview/

Wolverine did more for mutantkind as an Agent of SHIELD than he ever did as a member of the X-Men.

Source: https://screenrant.com/every-marvel-comics-late-80s-what-if-ranked/