In Chicago style, if the date of publication for a website is unknown, cite the access date (see the example in "Web page with neither author nor date").
Basic format for web pages:
Note
Author First Name Last Name, "Web Page Title," (Organization, Date), URL
Bibliography
Author Last Name, First Name. "Web Page Title." Organization, Date. URL
Notes
1. Gi Smith, "MLK Jr. Day of Service Continues to Engage Community," (Marietta College, January 21, 2020), https://www.marietta.edu/article/mlk-day-2020
Bibliography
Smith, Gi. "MLK Jr. Day of Service Continues to Engage Community." Marietta College, January 21, 2020.
https://www.marietta.edu/article/mlk-day-2020
Notes
1. "Bangladesh: Rohingya Children Get Access to Education," Amnesty International, last modified January 28, 2020, https://www.amnesty.org/en/latest/news/2020/01/bangladesh-rohingya-children-get-access-to-education/
Bibliography
Amnesty International. "Bangladesh: Rohingya Children Get Access to Education." January 28, 2020.
https://www.amnesty.org/en/latest/news/2020/01/bangladesh-rohingya-children-get-access-to-education/
Notes
1. "Oregon National Historic Trail (U.S. National Park Service)," National Parks Service (U.S. Department of the Interior), accessed January 29, 2020, https://www.nps.gov/oreg/index.htm
Bibliography
"Oregon National Historic Trail (U.S. National Park Service)." National Parks Service. U.S. Department of the Interior.
Accessed January 29, 2020. https://www.nps.gov/oreg/index.htm