JSFiddle - React, Tailwind, and code Playground

HTML

<div class="block_2">
    Содержание блока 2
    <div class="block_1">Содержание блока 1</div>
</div>

CSS

.block_1, .block_2 {
    width:200px;
    height:100px;
    border:1px solid black;
}

.block_1 {
    position: absolute;
    right: 100%;
    margin-right: 10px;
    top: 0;
}

.block_2 {
    margin-left:210px;
    position: relative;
}

.block_2:hover .block_1 {
    display: none;
}