Credence survives the end of the movie. With the war spreading to America and Grindlewald's supporters making life more dangerous for wizard and muggle alike, he makes it his mission to protect the people who have no one else looking out for them, and maybe get a little revenge along the way. To complicate matters, he's still ignorant of most magic, the obscurus is still slowly killing him, he's not in a great place mentally, and it's a struggle for him not to go full on dark wizard.