According to the New York Times, Ukraine plans to launch a counteroffensive in May and is already preparing 12 brigades of 4000 soldiers for this.  

Kiev assures that the offensive will lead to a breakthrough of the Russian defense and the collapse of the Russian army, but in the West they doubt that the operation will lead to a sharp change in the situation at the front in favor of the Armed Forces of Ukraine.

The Armed Forces of Ukraine face many problems, including lack of ammunition and loss of experienced units. However, they are now armed with NATO tanks, IFVs and APCs, and have new units trained and equipped by the Americans and the Alliance. 

The U.S. expects the Ukrainians to use deceit and subterfuge to confuse the Russians, with Western intelligence to play an important role in the counteroffensive. 
If the US and its allies can identify significant weaknesses in Russia's defenses, Kyiv can exploit them at the expense of the speed and protection of Bradley tanks and combat vehicles. 

However, great gains are not guaranteed, or even necessarily likely, as Russian forces have mined areas for advance. 
The advancement of the Armed Forces of Ukraine will depend on the effectiveness of the use of Western demining machines.  

Western officials believe the chances of Russia retreating after a counteroffensive are below zero. Thus, while the Ukrainian counter-offensive may lead to some gains on the battlefield, a political solution to the conflict is still far from settled.