Maps

There are currently 4 types of Maps in Overwatch. Assault (Capture Point), Escort (Payload), Hybrid (Assault & Escort), and Control (King of the Hill). 

ASSAULT (CAPTURE POINT)

Assault (Captire Point)'s objective is for the attacking team to capture the defending team's capture points. specifically, Capture Point A and Capture Point B. Capture point B does not become accessible until Capture point A has been captured. Points are captured by the attacking team occupying a point with no defending members around. The point is considered "Contested" if both attack and defending members are on it simultaneously. Capturing a point is not done immediately and points are captured faster with the more attacking members that are occupying it. 
Hanamura

Temple of Anubis Volskaya Industries

ESCORT (PAYLOAD)

Escort (Payload)'s objective is for the attacking team to escort the payload into the defending team's base. There are numerous checkpoints throughout the map increase the time for the attack to capture as well as change spawn locations for the attacking and/or defending team. The payload moves when the attacking team members are nearby with no defending members contesting. The payload moves faster when up to 3 attacking members are near it. The payload also heals attacking members. 

Dorado

Route66 Watchpoint: Gilbralter

HYBRID (ASSAULT & ESCORT)

Hybrid maps are both assault and escort objectives. They start with an assult objective that then leads to an escort objective. 

Hollywood

Hollywood Thumb

King's Row

Kings Row Thumb

Numbani

Numbani Thumb

CONTROL (KING OF THE HILL)

Control maps are designed with 1 central capture point that both teams are trying to control. Control is based on a tick system (up to 100). Whichever teams can hold the control the point the longest wins. These maps are played in a best of 3, with 3 different control points for each map. 
Illios Lijang Tower Nepal