Clustering markers from GeoJSON after adding data to layer in Leaflet

I am trying to add clusters in my leaflet map. I use overlayMaps which helps to choose one of the active layers, and in that case I want my marker to be a cluster. But it is not clustering. Again when I am trying with making any overlayMaps variable and put all the data its working the marker are cluster.

I want to show cluster in the map when the layer is active.

Plugin used: https://github.com/Leaflet/Leaflet.markercluster

var cluster = L.markerClusterGroup();
var geo = L.geoJSON(dataview, {
  onEachFeature: function (feature, layer) {
    layer.bindPopup(feature.properties.tags.name);
  },
});
geo.addTo(cluster);
var overlayMaps = {
  tourism: tourism,
  hospital: geo,
};
//add the layer control option
L.control.layers(baseMaps, overlayMaps).addTo(map);

var cluster = L.markerClusterGroup();
var geo = L.geoJSON(dataview, {
  onEachFeature: function (feature, layer) {
    layer.bindPopup(feature.properties.tags.name);
  },
});
geo.addTo(cluster);
var overlayMaps = {
  tourism: tourism,
  hospital: cluster,
};
//add the layer control option
L.control.layers(baseMaps, overlayMaps).addTo(map);