Alignment with React-Bootstrap

Technically your both the col are aligned next to each other perfectly.

Since the input is inside the form group, it gets the extra height as compared to the "clear" button.

If you remove label="Filter" from your code you can see the proper alignment.

The only way I see it now is to give a margin-top: 25px; to the button.

Here is the Demo

Basically, I gave a custom class to the button and in the css I added the margin I needed to align it.