Eschatology is the branch of Christian theology that deals with the end of the world and the coming of Jesus Christ. Different branches of Christianity have different beliefs about the end times and the return of Jesus.
For example, Catholics, Orthodox, and many Protestants believe that Jesus will return to Earth in a Second Coming and that this will be followed by a final judgement where some people will be saved or go to Heaven and others will be damned or go to Hell. However, some other Protestant denominations believe that there will be a "Rapture" before the Second Coming where all Christians will be immediately taken to Heaven.
Another big difference is in how people understand the "Millennium", which is a thousand year period mentioned in Revelation. Catholics and Orthodox believe the Millennium will be a time of peace and the kingdom of Heaven on Earth, while some Protestants believe it will be a literal period of one thousand years when Jesus will reign on Earth.
In general, Christians have different beliefs about what will happen in the end times and when Jesus will come back, but they all agree Jesus will come back and will judge the living and the dead.