Pope Francis has decided to stick --more or less, with the heraldic art, that is, his coat of arms that he had when he was called to the Order of Bishop and then as a cardinal. The most identifiable change made is the replacing of the red cardinal's galero and tassels with the papal keys and miter that Pope Benedict XVI chose for his arms in 2005 when he accepted the pontifical dignity but gone is the pallium. The other change is turning the star representing Mary, the Mother of God and the flower of nard representing Saint Joseph, to gold as opposed to silver. Add to the artscape is the image most associated to the Society of Jesus with the IHS sunburst. The Holy Family, hence, is illustrated here.
The keys of Saint Peter refer to the gospel passage of Saint Matthew 16:16 where Jesus says to Peter, "I will give you the keys of the kingdom." The keys represent the pastoral authority of Jesus given to Peter and thus to Peter's successor to forgive sins, and lead us to salvation. The silver key concerns things of earth, and the gold key things of heaven joined together by the red cord symbolizing the common witness of the blood of the Savior shed for humanity. You may want to read the Catechism on the Petrine ministry at paragraphs 880-882, the whole section "I believe in the holy Catholic Church is worth" some study and prayer.
"By having mercy and making decisions" by following Christ
~the way Pope Francis intends to exercise the Petrine ministry he's been called to~
The Holy See's statement in Italian.
