Do I need a Schengen visa?

My nationality Obligation to hold a visa
Cameroon  Yes (V) (M*: D,S) 
Central African Republic Yes (V)
Equatorial Guinea Yes (V) 

(V)
Third state members in possession of both a valid residence permit issued by a Schengen member state or a valid type D visa and a recognized and valid travel document are exempt from visa requirements.

(M*: D,S)
Holders of a diplomatic or service passport are exempt from the obligation to hold a visa if they travel to Switzerland on an official mission. 

Other nationalities

For other nationalities, please refer to the list on the webpage of the State Secretariat for Migration (SEM).

SEM – Overview of ID and visa provisions according to the nationality (Annex 1, List 1: nationality)

If you are obliged to hold a visa (yes), please apply for it and refer to the information on the webpage:

Where to apply for a Schengen visa?

If you are not obliged to hold a visa (no), you are allowed to enter Switzerland resp. the Schengen territory and stay up to 90 days within a 180-day period without any visa.