Warning! The following contains spoilers for the Superman & Lois episode "Heritage." Read at your own risk!
While Superman tries to handle issues on the homefront getting his family accustomed to life in Smallville, Captain Luthor is busy doing all he can in trying to obtain more kryptonite to destroy the hero. Surprisingly, this journey led the villain to a surprising character for help, and now I'm wondering if Sam Lane may just form an unlikely alliance with this show's big bad.
Luthor and Sam Lane had a brief conversation in the episode, in which the mysterious villain took a surprisingly desperate tone. Luthor informed Sam that on his planet, they were similar and had the same dislike for Superman. Luthor handed Sam a Superman dog tag and begged for the general to stop protecting Superman. Further conversation was cut short by Superman, who sprang into action after being signaled by Sam minutes beforehand.
The most interesting thing about this conversation that Superman & Lois fans may have picked up on is that Captain Luthor is seemingly telling the truth. The end of the episode showed Captain Luthor in a military uniform and down in a trench with several soldiers firing into the darkness. Unfortunately, their target appeared behind them, and a vast number of Luthor's squad was cut down by the laser vision of a black-suited Superman. Luthor was almost one of them but was saved at the last moment by the Sam Lane of his world, who died shortly after.
The scene seemingly confirmed two key things: that Luthor was a part of the military on his Earth and that Superman was indeed evil on his Earth. Captain Luthor is familiar with Sam because his counterpart on Luthor's Earth was also in the military, and apparently Sam's superior. This would explain why Luthor was tracking Sam specifically (though there are other possibilities) and felt he could get through to him if they spoke.
The part about Superman being evil is interesting, mainly because Captain Luthor seems to believe that the Superman of Superman & Lois is capable of the same atrocities. It has me curious whether or not the Superman of Captain Luthor's Earth was always evil, or if there was a sudden change in his character, which is why Captain Luthor is so adamant about trying to get Sam to turn on him.
Later in the episode, Sam certainly seemed to be thinking over what all he had heard. It wasn't more than just silently staring at a dog tag on his desk, but far more contemplation than I'd expect from someone whose son-in-law is the Man of Steel. I know Sam is mad about Clark moving the family out to Smallville and telling Jordan and Jon his secret identity, but that is no excuse for getting in cahoots with the Season 1 big bad!
With that being said, it seems clear that Captain Luthor may not be all that villainous after all. He does want to destroy Superman, but he does seem to have noble intentions and valid reasons for doing so. The way he spoke to Sam Lane did not seem like a man so far gone he couldn't be convinced Superman was actually someone different than the one he'd known on his Earth, but I guess we'll have to wait and see for sure.