Kleya Marki Unique has this section :
While Luthen Rael is active, Kleya can't be targeted and has +100% Evasion. If Cassian Andor (Undercover) is active and Luthen was not at the start of battle, Kleya gains the same benefits. The first time Luthen Rael's Health is reduced to 25% or less, he gains Damage Immunity for 1 turn and Kleya takes a bonus turn.
https://youtu.be/btVCY_6s5ms?si=cPBGJmtzWzTTMreU&t=115
Cassian with his intended team + FDC and you can see luthen getting Damage Immunity when he is all alone.
Luckily someone recorded their battle and upload it to youtube , hopefully this will help out with testing of it.
