CBS and the producers of the show were in negotiations to bring it back for one final season, expected to be anywhere between 13 and 18 episodes, so most people were expecting it to return.
Alas, it appears that those talks fell apart.
What's interesting is, CBS renewed at least two other shows that were doing worse in the ratings (Man With A Plan and Superior Donuts) than 2 Broke Girls, as well as a couple of shows that were only barely doing better than it was (Mom and Life In Pieces).
This might be a sign that there's a little more to the story, however.
See, CBS doesn't have any ownership in 2 Broke Girls, but they've consistently had to cover costs of the show. So, it may have rubbed them the wrong way when Warner Bros Television made a significant sum per episode when they sold the off-network rights.
Reportedly, they got almost $2 million an episode from TBS alone, so depending on how many other cable networks bought reruns Warner Bros. stood to make a hefty amount of money.
CBS is said to have tried to tap into the studio's back-end, after finding out, and that's apparently when things started to go south.
On the plus side... since CBS doesn't actually own 2 Broke Girls it's entirely possible that the producers could negotiate to bring it back for one final season on another network or streaming service.
While it may not be plausible that this would happen, The Mindy Project had lower ratings than 2 Broke Girls when FOX canceled it in 2015, but then Hulu swept in and the show has been very successful there.
Never say never.