Let’s have a recap of the two’s relationship then, shall we?
If we rewind back through the seasons, you may remember that when Max first moved to Hawkins, she was crushed on by both Lucas and Dustin. Over time, Max and Lucas form a romance, and have a pretty cute dance and first kiss at the Snowball dance.
Fast forward to the beginning of Season 4, and after a few ups and downs, it’s revealed that Max broke up with Lucas after dealing with the loss of Billy, her step-brother, and isolating herself from her friends. Then, after Max survives Vecna’s curse, all the while remembering the happiest moments of her life (many of which include Lucas), Lucas holds onto her, and the love the two have for each other is still very apparent. Yay!
So, when Part 2 of Season 4 put Max back at risk against Vecna, it could only end badly. The season finale gave us hope that Max and Lucas would come out stronger than ever after all they have been through, and then this hope was savagely ripped away from us. The last thing we see is Max basically dying in Lucas’s arms in a heart-wrenching scene, only to kind of survive (thanks to Eleven), and then end up in a coma. Heartbroken is not the word!
Source: https://www.buzzfeed.com/julietteperks/stranger-things-tweets-about-max-and-lucas