I know how much my fellow heathens and pagans get annoyed about things being called Christmas that are actually pagan. The upcoming conjunction of Jupiter and Saturn on December 21st 2020 will make the two planets appear as a single bright star to the naked eye, or like a double planet. Since it will be visible just after sundown it will be easier to view than some other sky occurrences, so people are excited about it. I've seen posts on the net saying the media calling it a Christmas star is wrong because it will be on the solstice, not on the 25th. The date of Christmas in the Bible is in lambing season, but the date established for the holiday by the Church as December 25 was supposed to be the solstice.
Christmas was originally established over the date of Roman Saturnalia, or on Sol Invictus (the Romans had multiple gods with overlapping areas of influence just like we heathens), which was on the winter soltice in accordance with the Julian calendar in use at the time. The winter solstice precesses, though. The Gregorian calendar reform re-established the drifted date of Christmas with the solstice. Eastern Orthodox who still follow the Julian calendar have their Christmas on January 7 according to our calendar, the Gregorian. Since the Gregorian calendar reform, the solstice precessed again. So the dates of Christmas and the solstice are off again, but they aren't supposed to be. Christmas was supposed to be on the solstice, so calling it a Christmas Star is not really wrong.
However, it is not going to look like a cross in the sky. It's going to look like a double planet, or if you have a telescope, like two planets close to each other.