Hi Shubham Dubey,
You can have non-persistent entity(e.g.datagridCheck(Boolean showDatagrid)) with showDatagrid default value set to FALSE and on your page you will have datagridCheck dataview(with object created using datasource microflow). In that dataview you can add checkbox for attribute showDatagrid which will be unchecked on firstLoad.
Now you have datagridCheck dataview with checkBox to select.
Then next you will add your datagrid2 (which will also takes input from datasource microflow) in dataview underneath checkbox.
For datagrid2 datasource microflow you needs to add dataview obj(datagridCheck) as additional input parameter and there have decision-
if showDatagrid true then retrieve data for datagrid2 and return
else return empty.
Hope this helps you.