The Swiss National Science Foundation supports internation collaborations:
Weave
At the National Science Centre (NCN), OPUS is approved as a funding instrument for the Weave procedure if the NCN acts as Lead Agency) or Weave-UNISONO (if the SNSF acts as Lead Agency).
SNF-NCN applications are part of the Project Funding instrument at SNF. In Project Funding, SNF applicants may have a maximum of two parallel grants, provided they are clearly thematically distinct from each other.
Details can be found here
Scientific Exchanges / Scholars at Risk
Scientific Exchanges is aimed at researchers who want to host their own scientific event in Switzerland, invite colleagues from abroad for a research visit to Switzerland, or visit their colleagues in another country..
Details can be found here