Agents of SHIELD returns for Season 3 on Tuesday, September 29th at 9pm ET; Agent Carter returns returns for its second season during mid-season.
Here's the description for the third season of SHIELD:
...the series will begin introducing new friends and foes inspired by the critically acclaimed SECRET WARRIORS comic series as well as the Inhuman Lash.
In the aftermath of S.H.I.E.L.D.’s battle with Jiaying and the Inhumans, Director Coulson will search the world for more powered people and assemble an extraordinary new team to deal with threats unlike the world has ever seen. However, the Agents of S.H.I.E.L.D. will soon find out they're not the only ones tracking down these new Inhumans.
Description for Agent Carter Season 2:
Dedicated to the fight against new atomic age threats in the wake of World War II, Peggy must now journey from New York City to Los Angeles for her most dangerous assignment yet. But even as she discovers new friends, a new home — and perhaps even a new love — she’s about to find out that the bright lights of the post-war Hollywood mask a more sinister threat to everyone she is sworn to protect.