There is no trainer because the game

has novel approach to detect tools used to make trainers
is using page_guard and other techniques to catch changes to the game or cause crashes
is using CRC checks, both on the game .exe and the copy of the game .exe which is being mirrored constantly
is using an entire .dll to constantly check the game for MANY things.
is using method to bring in and out the .exe of the game from encrypted manually mapped area of memory
is using crc checks in manually mapped code that checks the crc checks in the .dll which is checking the crc of the game .exe
likely the game isn't using server sided stuff for twitch sections of the game, and is sharing code for both SP and MP portions of the game, which IS a problem likely as people are likely to abuse trainer campaign options ONLINE.
is actively searching for tools, certain programs, and likely will make signatures of trainers and etc. as the game updates to kill anything being worked on.
and on and on

This is why there is NO CORRECTLY WORKING TRAINER for this game ANYWHERE. One 'source' has released something but it's rife with issues, WILL crash, doesn't work correctly in all cases (i.e. ammo, etc.), and is likely to get your account flagged and eventually banned.

We have NO CONTROL over what the developers put out or why or what their anti cheats or methods to thwart modding and game enhancement like we do here. I am also not some russian game hacking consortium that has either the time, the compunction, nor the lack of morals, to spend days on this one title to rip out the intertwined code that is in place specifically to stop people from being able to mod or cheat the game, including the campaign. The game devs simply DONT WANT YOU TO BE ABLE TO ENJOY THIS GAME ON YOUR COMPUTER AS YOU SEE FIT, even in SP mode. Go yell at them.

So until there is an elegant solution that is repeatably working, and is shared by the trainer making community, that WONT get your account banned, then for now we have NO ETA on this, and there may not be a trainer coming.

I've posted plenty of info from my own discoveries and working on this title on multiple sites to get discussion going and to discuss this novel approach, and I can certainly grab code and make options easily for this game. The PROBLEM is that the game is going to either quickly detect those code injections and crash, or eventually catch the code changes via CRC and then crash. If this happens during save, or they are taking info and making a ban list, then it's NOT GOOD for you, plus the fact these missions may take 20 mins and you are crashing repeatably 2-4 minutes into the game or when you pause, or when you pick up item X, etc.

The site isn't Halo Cheats. It's a site with cheats for many games, and we have to support them all. I've done all I can and can do with this title for now.

best,
Cal