The Civil War in Yemen is a conflict initiated in 2014 between the Houthi Movement and Yemeni President Abdrabbuh Mansur Hadi. In the time since, 200,000 people have been killed, 100,000 civilians have died of starvation or cholera, and millions have been displaced. The war represents not just the internal political struggles of Yemen, but also a proxy conflict between Iran (supporting the Houthis) and Saudi Arabia (supporting the Hadi government), with support from the United States via Saudi Arabia.
In March 2019, US Congress voted to end support for the Saudi-led campaign, but this action was vetoed by US President Donald Trump. On Feb 4th, shortly after his inauguration, President Joe Biden cut support for the Saudi-led campaign. With Biden's other attempts at opening negotiations with Iran, it's possible the US may be motivated enough to negotiate a peace agreement.
In Vox's Future Perfect, Dylan Matthews gives this a 60% of occurring this year:
The biggest development is Joe Biden’s election. The US is not the main actor in the civil war, but it is an important actor for the support it has given Saudi Arabia (including actual special forces troops on the ground). Bipartisan pressure from Congress to end support for the Saudi air war has been mounting throughout Trump’s term, and a president less close to Saudi de facto leader Mohammed bin Salman seems likelier to yield to that pressure.
The Biden campaign in fact promised to end support for the Saudis in Yemen, and incoming senior administration officials — Secretary of State-designate Antony Blinken, Director of National Intelligence-designate Avril Haines, National Security Adviser-designate Jake Sullivan, and UN Ambassador-designate Linda Thomas-Greenfield — signed an open letter urging the same.
Will there be a cease-fire or peace agreement in the Yemeni Civil War by 2022-01-01?
This question will resolve positively if there is a 30-day period in 2021 of cease-fire or peace in over 90% of territory in Yemen, without unambiguous violations (aggressive violence not condemned or reprimanded by the aggressor leadership).