Welcome to the community. 
Please take the time to use the search button before making new posts. Your concern has already been addressed previously.
Here’s an extensive educational post on the matter: My antivirus marked WeMod as a Trojan - #2 by Ravenfyre.
Long story short, it’s a false positive, mainly but because WeMod’s security encryption cannot be understood by anti-viruses - which is a good thing because it means our trainers cannot be compromised by shady actors, unlike certain other trainer download locations.