Do we know how this season connects with the previous season yet? Derek bit Jackson and he started becoming the kanima (1-2). Derek's alpha status spreads through the werewolf news and the Alpha Pack wants to recruit him. (2-3). Jennifer's earthquake releases the Nogitsune and allows it to possess Stiles (3A-3B). Kate comes back because she heard somehow that Allison died (3B-4). I've tried thinking about it, but, I can't really see a connecting thread yet between 4 and 5.
In theory the seasons don’t have to connect like that. It was just convenient for them to set them up with lead ins like that. It makes for good writing and such.
I don’t think 4 and 5 share that connection like you mentioned with the others. It’s intentional. There’s been a bit of a time skip (summer) and now things are picking up. I feel with Derek/Tyler H. leaving, they wanted to sort of start fresh and they have with this season.
If you really want a connection though, there is Dr. Valeck. He appeared in 4 to help Deaton with the Benefactor and to torture Peter later. Also, Eichen House remains a key player as it was in 3B and 4. So, there’s still connections.