<div class="grid">
  <div class="nested-grid">
    <div class="item"></div>
  </div>
</div>

.grid {
  background-color: deepskyblue;
  height: 300px;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  grid-template-rows: repeat(3, 1fr);
}
.nested-grid {
  background-color: mediumblue;
  grid-column: 2 / 5;
  grid-row: 1 / 3;
  display: inherit;
  grid-template-columns: inherit;
  grid-template-rows: inherit;
}
.item {
  background-color: black;
  grid-column: 2 / 3;
  grid-row: inherit;  
}