Powerapps build your string to creae an html link
<div style="background-color:#000000;width:100%;"><code><a href="https://mySP.sharepoint.com/sites/DfSite/Lists/Initiatives/DispForm.aspx?ID="; InitiativeId; "" style="color:#FFFFFF;height:100px">";SelectedInitiative.Titre;"</a></code></div>