This is pure speculation at this point as there is in fact no actual mentioning of a sequel, but a number of job listings which popped up at IO Interactive’s website might be hinting at Kane & Lynch 3 being in development.
Both Kane & Lynch: Dead Men and Kane & Lynch 2: Dog Days got hit hard by critics at the time of their release, but the idea, concept and world of the franchise show there is potential make a great game yet. And some of these job listings we just mentioned may just reflect that is the opinion of IO Interactive and now-publisher Square Enix as well.
Or how about the hunt for [senior] game programmers to work on a as of yet “unannounced AAA action title,” or senior multiplayer programmers for a “unannounced 3rd person game with strong cooperative multiplayer elements.” Given the latter was a part of Kane & Lynch 2: Dog Men, it sure seems a number 3 in the series is more than a likely candidate to be developed.
That said, we reiterate that this is merely speculation. Time will tell.