Alongside being much less menu-heavy, having better tutorials, and a much prettier game engine to play with, Crusader Kings III will make major alterations to its core gameplay, namely its RPG development system. One of those is the Lifestyle perks, which will no longer be temporary buffs and debuffs depending on your preference, but lifelong goals with skilltrees that you'll work through to unlock the most fanciful and impressive traits.
Like Crusader Kings II, there will be events throughout your life that are only accessible when using that particular lifestyle focus. But you'll also have interactions with perks you've unlocked, as well as existing traits and you'll be able to play your character much more true to their personality than you could in previous entries in the series.
You don't even need to follow through with these events right away. For some of them, you'll have the option to sit on your hidden knowledge, your manipulation, your potential torturous death, and use it later to your advantage, when it is most useful.
These sorts of schemes have been massively expanded on in CK3, with much more nuanced choices. That means finding the right allies to support you in attacking or seducing them, not just grabbing everyone you can based on a percentage modifier, as it is in CK2.
There's lots more to come in CK3 and we'll learn more about it all as we edge closer to the game's release later in 2020.