Jokic also led in Win Shares last year. Currently Luka is slightly behind Derrick White in that category.
The one person who can prevent Luka from the PTS/REB/AST trifecta is Jayson Tatum, who is at the moment 20 rebounds behind Luka. Points and Assists are locked up as long as Luka doesn't miss any games.

What's extra impressive about Luka's run is that he's tied for the team lead in individual playoff DRTG (109; BBREF) and he has the second-best On Court playoff Team DRTG (110; NBA.com) among DAL starters (DJJ leads at 108). So he's doing it on both ends.
Max 5 more games left in this postseason. We'll see if he can hold on to the REB lead.