A group of authors from Italy, Spain and China suggest that Cannabidiol (CBD) has the potential to limit the severity and progression of the disease for several reasons: CBD:
(a) down-regulates the expression of the two key receptors for SARS-CoV2 in several models of human epithelia,
(b) mitigates cytokine production for acute lung injury
(c) displays a direct antiviral activity and
(d) inhibits pulmonary fibrosis in recovered patients.

The authors hope their hypothesis inspires studies testing cannabidiol against the COVID-19.

Br J Pharmacol. 2020 Nov;177(21). Esposito et al. Full text.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7300643/

Cannadibidiol recognizes several receptor targets and displays a multifaceted immunomodulatory activity that could limit the severity of SARS‐CoV2 infection: it downregulates ACE‐2 receptors, SARS‐CoV2 gateway, it can mitigate cytokines release and reduce pulmonary inflammation and fibrosis through PPARγ receptors