If you plan to use a standard SATA SSD that looks like credit card, no need for a PCIe card or PCIe adapter.  You would however, need a 3.5" to 2.5" adapter to go inside the blue caddy to hold the SSD. T7500 might be to old to take an m.2 nvme SSD, especially with Legacy BIOS..  However if it does, others can always chime in and there might be forum posts on it as well.  Not sure which one you plan on.
Hi, I have a T7500 and want to change the C drive o/s to a ssd drive. I have been told that I need a PCIe card for this to work. I know there are compatibility issues with these cards as a few years ago I had to get one to use an external 4 drive box. (not raid) and I had  to buy 2 before one worked. It is no longer in the 7500 and it is so long ago I forget which one worked. Any guidance please.  I do need one on the economical side of the the purchase. Covid lock downs  killed the bank income and account. Thank you  
Need compatible PCe card for T7500 so I can use ssd as Win 10 o/s drive