Could it be the COVID jab?

Nah. Of course not. /s

But note: I've not found anything about Bamba's vax status, so it MIGHT be something else in this case.

https://www.cbssports.com/boxing/news/paul-bamba-who-broke-a-mike-tyson-record-that-stood-for-38-years-dies-six-days-after-14th-fight-of-2024/

Boxer Paul Bamba has died at the age of 35 just days after winning the WBA gold cruiserweight title. Bamba's manager, Grammy Award winner Ne-Yo, announced the fighter's death on social media.

On Dec. 21, Bamba knocked out Rogelio Medina in New Jersey for his 14th consecutive stoppage win in the span of 12 months. In the process, Bamba broke Mike Tyson's record for most professional fights in a one-year span.

Less than one week later, Ne-Yo, whose real name is Shaffer Chimere Smith, issued a statement announcing that Bamba had died at just 35 years old.