John Wick wins his freedom by killing the Marquis in the duel at Sacré-Cœur, but the film closes on a gravestone with his name on it, so his fate stays open.
The mechanics come first. The Harbinger honors the result by releasing John and Caine from their obligations and giving Winston back his position, which formally ends the war with the High Table John Wick that began when John killed one of its members inside the Continental in Chapter 3. John collapses at the top of the steps, badly hurt. Later, Winston and the Bowery King visit a gravestone with John's name on it, next to the grave of his wife Helen.
In my opinion, the strongest beat is the third shot. Winston has agreed to be John's second with his own life tied to the result, and it is Winston who points out that John has not yet fired his third shot after Caine wounds him. That means the rules the film built in Berlin and Paris decide the outcome, rather than a last minute escape.
So, is John dead? It could be argued that the grave is a straightforward ending, because the High Table has released him and the story is built around closing his war. The counter argument is that Chapter 3 also left him apparently finished after Winston shot him, and he was alive when this film began. I read the ending as deliberately open, not a confirmed death.
On what comes next, Lionsgate announced at CinemaCon on April 1, 2025 that it is developing John Wick: Chapter 5 with Keanu Reeves, Chad Stahelski and Thunder Road, and both TheWrap and Screen Daily report no release date. Reeves also appears as John in Ballerina, but that spin-off is set during Chapter 3 and so does not answer what happened in Paris. The john wick 5 page tracks the status.