Evoking the design of ancient bows, the high impact Cernos is perfect for hunting down highly shielded enemies.
The Cernos is a Tenno bow, specializing in damaging shields by specializing in Impact damage. Much like other bows, it functions with a charge mechanic, and sports very high accuracy at range, despite the arrow drop. It is most effective against the Corpus as it can easily break through their shields, but is less effective against the Grineer and Infested, due to a lack of other damage types.
Due to the weapon's high Impact damage but low Puncture and Slash damage, consider using this to drain the enemies' shield first then finish them with other weapons which have higher damage where the Cernos lacks. Alternatively, consider making this your main bow for going against Corpus troops, the majority of which have high shields but very low health.