On a personal level, Her Majesty will host grandson Prince Harry's wedding to Meghan Markle in the Spring, and she will then celebrate her 92nd birthday in April – just ahead of her sixth great-grandchild, the new Cambridge prince or princess.
Her Majesty will maintain a full diary of engagements throughout 2018, but she will also continue to delegate to her children and grandchildren – predominantly Prince Charles and Prince William. Charles represented his mother in Sri Lanka at the Commonwealth Heads of Government meeting in 2013, but it's likely since the global summit is in 2018 held in London, that the queen will attend herself. We won't be seeing her at the annual State Opening of Parliament, though, as it has been cancelled to give Members of Parliament more time to deal with Brexit laws.