If the company already have Tableau is there any possible way to use it with Qlik Sense (like connect or link to each other)? And if that possible which area should this two BI tools working together? Or using Tableau dashboard in Qlik Sense without recreate all dashboard over again.
I'm not very familiar with Tableau, but it offers some kind of API for interacting. If these APIs are somewhere similar to what Qlik offers in Qlik Sense then you might be able to create a mashup containing both QS and T elements.
I know of people who are forced by the company standard to use Tableau for visualizations. But since the data preparation options are so bad in it, they just use Qlik Sense Desktop to extract, transform and test source data (about 80% of real BI work), also aggregate (as Tableau has inferior performance), store it into TXT files and then load it to Tableau to create some fancy charts. The real problem that thay cannot solve is that Tableau does not have associative experience out-of-the-box.
So (1) data prep and (2) query performance on 10+M datasets is where Qlik really outperforms.
But I guess there are more problems than value = no associative experience, lower performance of Tableau objects, higher admin costs...