Being cancerous has nothing to do with how many combos you can get but how annoying your team can be for the opponent. Usually a cancer team mainly applies to water or earth team. There's two types of cancer team for water main. The immortal water team focuses on making sure heals always happen. The top-tier teams usually have roshi, tsunade hokage, han, sailor sakura, and a couple of other ninjas that would work in these types of teams. The water blitz team that has mei, mabui, and gnw tenten is popular, especially for f2p, because it's easy to build compared to other p2w teams, each turn you can deliver high damage, and you'll face a lot of this type of team lvl 70+ cross server events.

I assume you just started playing since you are using a team that is expected for someone to start with. Just plan out what main you want to play with and save your seal scrolls for kage treasure so you can begin building a team.