I think that there's at least a decent chance that they'll get another season. It all depends on how well it performs on HBO Max, but considering the large following Young Justice has and how they managed to get a third season after all these years, I could see it doing well enough to warrant more episodes. Plus, HBO Max needs more new content and having a fan favorite series like Young Justice would potentially make more people subscribe to their service. It's all too early to say for sure either way. If they get renewed, hopefully it is sooner than what happened with season four.