The College of American Pathologists (CAP) has a webpage dedicated to upcoming and recently finished CAP guidelines - here.
One of the newest is an in-progress guideline for PD-L1 testing - here. The PD-L1 webpage states, "The primary goal of this guideline is to develop evidence-based recommendations for the testing of immunotherapy/immunomodulatory biomarkers including PD-L1 and TMB in patients with non-small cell lung cancer (NSCLC)."
The webpage provides you with 8 "key pre analytical questions" and creates an open comment period on proposed guideline conclusions which is open to April 23. There's a link to a 7-page bibliography, and a link to a PDF of 6 proposed summary recommendations. You can click on a comment box which collects basic information on the commenter (e.g. profession, such as pathologist) and allows step by step comment on each of the recommendations.
Comments are open until April 23.
At the work in progress webpage here, ten topics are listed: MSI testing, glioma evaluation, monoclonal gammopathies workup, HPV lesion terminology (ano genital), PDL1, whole slide imaging, IHC validation (in general), amyloidosis protocols, HPV testing rules for H&N cancer, TKI testing in lung cancer.