How did T’Challa die?

Though Black Panther: Wakanda Forever opens with the passing of T’Challa we’re never told how he dies. We learn later that he largely kept it a secret and most people found out when it was too late. Which is almost an exact parallel to actor Chadwick Boseman himself, who had been battling colon cancer for years but only told close friends and family.
The film doesn’t offer a specific answer to this question but director Ryan Coogler’s choice to parallel the fiction of T’Challa’s passing with the reality of Boseman’s allow you to draw your own conclusions.