Pupa, Ajin Recommendations
In both shows the main character discovers he's immortal and has to flee or else they'd become the subject of some cruel experiments. I recommend it one way because Pupa's plot doesn't make sense, while Ajin's storyline is coherent and engaging. so if you liked Pupa go ahead and give Ajin a try.
We have in here some similar stuff, like the torture/experiment on the wiked for more information, and at some point, the organs were removed and grew back again. The polt is not actually the same, but there are similarities on the way the main characters uses their powers to fulfill their actions