Nopee, it’s stand alone but the characters from other parts make cameos from time to time to give way in promoting those characters’ stories and to promote their parts getting adapted(potentially) into manhwas(like PASSION and RAGA)
No, you don't need to. And a lot of readers liked KMIYC much more than KML.
But be aware that both are part of the same universe and take place around the same time, so some characters appear in both stories (those are not just cameos as mentioned above) and some events take place at the same time.
do we have to read kiss me, liar before this?