Paulo Costa responds to Bogdan Guskov callout

Paulo Costa has responded to a callout from Bogdan Guskov on social media. The post is limited in details, providing only that the Brazilian middleweight acknowledged Guskov's challenge. The nature or content of Costa's specific response is not detailed in the source material. This exchange represents potential interest in a matchup between the two middleweights, though no official fight announcement has been made. Further context about the timing or substance of the callout and response would be needed for a complete picture.