Most of the sanction packages introduced by both the EU and the US include no concrete end conditions. Take, for example, those introduced in EU Council Decision 2014/145/CFSP. Article 6 states:
This Decision shall be kept under constant review. It shall be
renewed, or amended as appropriate, if the Council deems that
its objectives have not been met.
Since 2014, this council decision has been frequently amended to extend the application of the sanctions or to introduce further sanctions to the package, most recently on March 2nd 2022. There are no references to conditions that would trigger an end to the sanctions package, instead, the EU Council reserves the right to renew, amend or lift the sanctions depending on its opinion on whether the objectives of the sanctions have been met.
Similarly, none of the US sanctions packages implemented in various executive orders, in particular, orders 13660, 13661, 13662 and 13685 issued by President Obama, order 13849 issued by President Trump and order 14065 issued by President Biden provide conditions which would trigger the automatic lifting of sanctions.
Some of the sanctions packages imposed by the US Congress have included termination criteria, for example the Ukraine Freedom Support Act of 2014. Subsection (h) of section 4: Sanctions relating to the Defense and Energy Sectors of the Russian Federation states:
Except as provided in paragraph (2), this
section, and sanctions imposed under this section, shall terminate on the date on which the President submits to the appropriate congressional committees a certification that the Government of the Russian Federation has ceased ordering, controlling, or otherwise directing, supporting, or financing, significant acts intended to undermine the peace, security, stability, sovereignty, or territorial integrity of Ukraine, including through an agreement between the appropriate parties.
The Countering America's Adversaries Through Sanctions Act of 2017 also includes various provisions by which the President may terminate sanctions on individuals if they receive various undertakings from that individual. In these cases though, the power still rests with the President to terminate the sanctions, rather than them automatically lapsing at the end of the war.
Informally, there have also been some comments made by leaders over the past eight or so years which set out end conditions for the sanctions. For example, in a speech to the UN General Assembly in September 2014, President Obama welcomed the newly agreed ceasefire in Ukraine under the signing of the first Minsk agreement:
Moreover, a different path is available -- the path of diplomacy and peace, and the ideals this institution is designed to uphold. The recent cease-fire agreement in Ukraine offers an opening to achieve those objectives. If Russia takes that path -- a path that for stretches of the post-Cold War period resulted in prosperity for the Russian people -- then we will lift our sanctions and welcome Russia’s role in addressing common challenges. After all, that’s what the United States and Russia have been able to do in past years -- from reducing our nuclear stockpiles to meeting our obligations under the Nuclear Nonproliferation Treaty, to cooperating to remove and destroy Syria’s declared chemical weapons. And that’s the kind of cooperation we are prepared to pursue again -- if Russia changes course.
In January 2015, France's President Hollande also signalled his willingness to lift sanctions on Russia if progress was made in the Minsk II talks. These sanctions were not ultimately lifted, which illustrates the futility of trying to predict when the current tranche of sanctions might be lifted.