The handle leaks and I removed the screw in the handle and it won't even budge when I try to take it off any suggestions?

I assume you are referring to the Hangrohe. https://images.homedepot-static.com/catalog/pdfimages/a7/a79e5618-65fc-4e21-9a59-dd8bcc4773aa.pdf
It appears there are detents that hold the handle so push ON and pull OFF. Firm grip and pull should remove the handle. Although, if yours has leaked for weeks/months, corrosion/deposits under handle may make it difficult. If coldle hand doesn't budge, try removing the hot as it has not been leaking and may pop off with less effort. Then go after the other. Note; you may as well replace both cartridges.

you need to unscrew the lever handle and in the bottom of the threaded recess you will see a 4mm allen head screw. Loosen this a couple of turns with a 4mm allen key and the complete handle will slide off to give you access to the cartridge

Read more: https://www.diynot.com/diy/threads/removing-blanco-tap-handles.378938/#ixzz70WYg3ojT

If the set screw has been remove try rocking handle back and forth while pulling in it
https://www.homedepot.com/catalog/pdfimages/21/21fea4c4-1155-4df8-a912-73d0b2113e6b.pdf

Get a screw extractor kit, if your lucky you can get the screw extractor to wedge into whats left of the hex and force it out, but even then it might not come out, i would recommend getting some penetrating oil, like PB Blaster, regular old WD-40 is ok for lubricating but its not a penetrating fluid, soak it in the morning and go about your day and then dry it in the evening, if it still won't budge you might have to remove the whole faucet from the sink and take it to an area you can clearly work on it and drill out the set screw with a drill bit that fits in the hex to make the hole in the center of it deeper to give the screw extractor a better grip. I've been there done that a few times, it takes time and patience, and in the end they cant all be saved.

It is unclear to me exactly what you are trying to remove....given
that, I suggest a spray lubricant and let sit to work in....if the screw
head is not stripped keep it so...a long handled screwdriver will
work better...use more lubricant if you have to- do not force.

Regards,
Dennis

Spray it with WD40 , take a minute or two and try removing it .

Try heating it with a torch and use PB Blaster on it.

replace rubber seal in tap need to unscrew the nut to get at it

There is a plastic retainer not with two tabs used for removal. You will need a removal tool to get this retainer off. Any plumbing supply that carries Moen should have this tool.
After removing the retainer nut, the cartridge pulls right out. Good luck!

if you have taken out screw then pull off if you have a handle puller use it