is it possible that i use only cis cloud.
if i install comodo firewal , can this find any threat in cloud?
COMODO Firewall does use the cloud rating system, which has good files, unrecognized files, and malicious files, so yes, Comodo Firewall can find threats in the cloud without downloading that massive 300+MB database.
Video of Comodo Cloud Scanner in action at 3:29:
Old video but the cloud scanning should still work.
COMODO should move old definitions to cloud to reduce DB size imo.