Leaping further and higher and running faster is not worth the investment at our existing tech level. The effort and resources put into it would be much more efficiently invested elsewhere in almost all cases, with some possible exceptions.
Military research though has a lot to do with extracting money from governments, and with the reasoning of being able to do new things more effectively. In the US particularly, there is a focus on reducing risking one’s own humans, and solving various perceived problems.
In that context, there could be some roles eventually for an exoskeleton. I haven’t looked much at the latest military toy projects lately, but immediately I can see that it could be sold as eventually a way to get soldiers an advantage in some situations. Mainly I think it would not be so much about better movement compared to a plain soldier, but about being able to carry enough protection to resist most enemy anti-personnel weapons. Carrying more weapons would also be helpful. That seems like it could be eventually reasonable. If you’re imagining facing many opponents on foot with guns, particularly in urban settings, then something with the ability to go into buildings like a person, but very hard to injure with bullets or grenades, could be advantageous if your goal is to minimize your own casualties. It’d probably tend to reduce enemy morale if they had to worry about facing them.
However I tend to expect that’s a way off being effective, and that it will probably be less expensive to come up with counters. For example, it’s probably going to be hard to make such a thing invulnerable to armor-piercing weapons such as shaped-charges (think RPG, but specialized against armored suits).
Seems like a USA kind of thing. Though the Japanese love robots.
The farther into the future, the more likely it seems, due to improving technology (assuming climate change or other human folly isn’t going to wipe us out), and new situations.
(Oh, and your tag “mechanized infantry” traditionally just refers to infantry formations who are assigned armored vehicles (armored personnel carriers) to get into combat with.)