Queen Elizabethhas reigned since 1952 when her father, King George VI, died.
The queen’s own ascent to the throne didn’t come about in a traditional way.
As part of his role as king, Edward was head of The Church of England.

Simpson had been divorced twice, and The Archbishop of Canterbury wouldn’t permit a marriage between the two.
PerNational Geographic, here’s where Edward and Harry’s paths diverge.
But his death meant that, at age 25, she would officially become queen.

PerDistractify, Prince Philip’s recent death didn’t have any impact on the line of succession.
What happens if Prince Charles dies before his mother?
In the unlikely event that Prince Charles dies before Queen Elizabeth, the line of succession won’t change.

Per CheatSheet, the Prince of Wales title signifies that a person is heir apparent.
“Only if Charles dies before the queen would William become king when the queen dies.”
Prince William will then take the throne when his father dies or steps down.

So unless he dies before his father, Prince William will become king.