The start of Conclave has one flaw with the secret cardinal explained by David Gibson, Director of the Center on Religion and Culture at Fordham University. The story of Conclave follows Cardinal Lawrence, who is tasked with organizing a conclave of cardinals to choose a new pope. As all the cardinals are about to be sequestered, Cardinal Benitez arrives and reveals that the previous pope secretly named him a cardinal. The cast of Conclave includes Ralph Fiennes, Stanley Tucci, John Lithgow, Isabella Rossellini, and Carlos Diehz.

https://screenrant.com/conclave-movie-cardinal-benitez-secret-pope-expert-reaction/