https://www.thegamer.com/mortal-kombat-11-sweet-tooth-rumor/

https://www.gamerevolution.com/news/547197-mortal-kombat-11-twisted-metal-dlc-possibly-teased

Sweet Tooth is being rumored to join the Mortal Kombat 11 roster. A tweet by Mortal Kombat Twitter's account wrote
"An #IceKreamTruck during #E32019 would be fun, right?" 
And since Sweet Tooth is heavily associated with an ice cream truck, the conclusion is that the hint is about him.
Sweet Tooth had been rumored for MK9 and MKXL, and MK9 did have Kratos in the roster (as a Playstation exclusive), plus Sony has a TM TV show in the works, so this newest rumor may actually be reality and Needles Kane may be officially joining the Mortal Kombat universe, but so far, the only guest character confirmed as DLC is Spawn.

Great news! MK would be the shot-in-the-arm the TM series needs to get more fans interested. Also, this is something TM fans can finally look forward to after waiting so long for something new...

Imagine being able to swap skins for different iterations of Sweet Tooth like TM2, Black, TMPS3 and why not TM1 and Head-On Sweet Tooth while we're at it?...

TwistedChains wrote on 07/02/19 at 18:41:15:

Great news! MK would be the shot-in-the-arm the TM series needs to get more fans interested. Also, this is something TM fans can finally look forward to after waiting so long for something new... Imagine being able to swap skins for different iterations of Sweet Tooth like TM2, Black, TMPS3 and why not TM1 and Head-On Sweet Tooth while we're at it?...

I hope it happens and will be a little pissed when it turns out to be just a rumor.

but i do think ST is perfect for the MK universe and with MK11's kustomization and many skins, I could totally see all the past Sweet Tooths represented.
Imagine what his ending could be too, with Sweet Tooth controlling Kronika's hourglass? Maybe in his "new era" he gets to control both Twisted Metal and Mortal Kombat?
And imagine all the character intro interactions?
Like;
Kano - Ya gonna twist a balloon for me, mate?
Sweet Tooth - Shut up and bleed motherfucker.
Kano - Never did like clowns...

I thought all of the DLC leaked already. Maybe they will release console exclusive fighters.

It's not likely.  Some have speculated that IceKreamTruck is a twist on the phrase "I scream" as we all know.  It could be indicating the reveal of Sindel, because of her powerful screams.

Gosh dang it, Ed Boon!

For what it’s worth Bruce Campbell is denying involvement in MK11 so that chainsaw could possibly be associated with Sweet Tooth, doubtful though.

The Sweet Tooth as a Mortal Kombat Guest Fighter Rumor has finally been confirmed to be true.

"Sweet Tooth has also (more than once) been DAMN close to being a guest fighter in MK games." -Ed Boon

So Sweet Tooth never made the cut but he is sort of part of Mortal Kombat history now.

I imagine his fighting style would have been similar to a guest fighter like Leatherface or Jason who rely on a weapon, as Sweet Tooth is an expert at killing with weapons, and was never portrayed as much of a great fighter in most of the games although in TM Black and TM 2012 his physical toughness is implied.

Apparently Ed Boons/Midway Games contemplated making an arcade Twisted Metal game with Jaffe at some point "decades ago" (2 decades ago) as well. Probably best that didn't happen, but pretty interesting regardless.

Sources:
https://www.svg.com/608272/mortal-kombat-creator-reveals-the-one-character-that-just-missed-the-cut/
https://gamerant.com/twisted-metal-sweet-tooth-mortal-kombat-guest-fighter/
https://screenrant.com/mortal-kombat-twisted-metal-crossover/
https://www.thegamer.com/ed-boon-sweet-tooth-mortal-kombat/