Yeah, he only originally joined because the government insisted they had to have a black member, and Black Panther wasn't on the team at the time. He's been on and off ever since though, and was on Luke Cage's Mighty Avengers when he became Cap. When the teams were restructured after Secret Wars, Sam was Tony's first recruit, and he became leader when Tony was rendered comatose in Civil War II. Sadly, he hasn't had a good showing in his tenure. First Ms Marvel leaves and forms her own team, recruiting the two teen boys (Nova and Spidey) who had also left shortly before. Then Kang nearly kills the team in the cradle, and he accidentally teaches a past version of the team the Avengers Assemble line! Then Secret Empire happened, prompting him to ditch the Captain America identity and costing the team their base. Nadia saved the day there, providing a temporary base until the Human Torch gave them the Avengers Mansion. Then the Worlds Collide story happened, which almost got Viv Vision killed. And now No Surrender, which they apparently didn't see coming. It's not Sam's fault, but it's been one disaster after another.