The war in Ukraine will likely intensify this summer. Here's what to know

You might look at the war in Ukraine — now over two years old — and think it grinds on with little or no headway being made by either side. But a great deal still hangs in the balance.

A $60 billion U.S. military aid package is gradually making its way to Ukraine, and the White House has made incremental shifts on Ukraine's ability to target Russia directly — developments that will have profound repercussions for years to come. More immediately, fighting in the Russia-Ukraine war has tended to pick up during the summer, when the warmer, drier weather makes it easier for both sides to maneuver.

With all that in mind, here are five key regions and themes to be aware of over the months ahead:

The battle over Kharkiv and why that matters

Russian President Vladimir Putin tried taking Kharkiv, Ukraine's second-largest city, at the beginning of the full-scale invasion in early 2022, but failed. Russia is trying again to move on the city, which is a short distance from the border with Russia. The most intense fighting at the moment is taking place just outside Kharkiv.

Fred Kagan, a senior fellow and the director of the Critical Threats Project at the American Enterprise Institute, said there are two plausible explanations for why Russia is targeting Kharkiv. First, Russia may be attempting to thin out Ukraine's lines throughout the country by forcing Ukraine to shift troops from other areas to the Kharkiv region.

Second, Russia may be trying to get close enough to the city so it can use traditional artillery to keep the city under constant attack. Right now, Russia still has to rely on longer-range rockets and missiles.

"If they can do that, then they will be in a position to begin to do really massive damage to the city, much