My organization's IT policies have tightened up with regard to making external connections, and I'm getting errors like

localHub=TRUE
library(celldex)
mouse_imm_ref <- celldex::ImmGenData()

Error in value[[3L]](cond) : failed to connect
  reason: SSL certificate problem: unable to get local issuer certificate
  Consider rerunning with 'localHub=TRUE'

I think the issue is that there is some kind of list of allowed locations, and I need to ask IT to add the locations that celldex queries to that list. But looking at the function definitions is not helping me to know what exactly I need to request of IT. Can you help me to know where to look for the data locations, so I can ask IT to allow connections there? Is it maybe just github or git.bioconductor.org?

I've seen this error with Ubuntu 20.04 and the Ensembl mirror sites, where there's some oddity in the SSL certificates. It comes up often enough I put it in the vignette

Can't promise this will work with Celldex (or that it's a good idea), but maybe try running this:

httr::set_config(httr::config(ssl_verifypeer = FALSE))

If that doesn't work, I think the server it's connecting to is https://experimenthub.bioconductor.org