Hello @antonio81m,
Thank You for posting your query onto the Forum.
Well I sense that you want to analyze the current year data with the previous year where previous years data will be static inspite of selections made into the slicers pertaining to the months. That is, you want to compare current year or months data with the end month of the previous financial year.
Just couple of days back I provided the solution based on this sort of requirement. I’m providing a link below for the reference of the solution provided on that post from where you can also download the working of my PBIX files for the better understanding of the concept.
Also without looking at the data or working of your file it will be very much difficult for the forum members to judge and provide the results efficiently and in a better manner.
Hoping you find this useful and meets your requirements that you’ve been looking for. 
Note: Please click onto the link in order to view the entire post and not onto the expand/collapse button.
Thanks and Warm Regards,
Harsh